How to allow only a number (digits and decimal point) to be typed in an input?

I am new to angularjs. I am wondering what is the way to allow only a valid number typed into a textbox. For example, user can type in "1.25", but cannot type in "1.a" or "1..". When user try to type in the next character which will make it an invalid number, he cannot type it in.

Thanks in advance.

I wrote a working CodePen example to demonstrate a great way of filtering numeric user input. The directive currently only allows positive integers, but the regex can easily be updated to support any desired numeric format.

My directive is easy to use:

<input type="text" ng-model="employee.age" valid-number />

The directive is very easy to understand:

var app = angular.module('myApp', []);

app.controller('MainCtrl', function($scope) {
});

app.directive('validNumber', function() {
  return {
    require: '?ngModel',
    link: function(scope, element, attrs, ngModelCtrl) {
      if(!ngModelCtrl) {
        return; 
      }
      
      ngModelCtrl.$parsers.push(function(val) {
        if (angular.isUndefined(val)) {
            var val = '';
        }
        var clean = val.replace( /[^0-9]+/g, '');
        if (val !== clean) {
          ngModelCtrl.$setViewValue(clean);
          ngModelCtrl.$render();
        }
        return clean;
      });
      
      element.bind('keypress', function(event) {
        if(event.keyCode === 32) {
          event.preventDefault();
        }
      });
    }
  };
});

I want to emphasize that keeping model references out of the directive is important.

I hope you find this helpful.

Big thanks to Sean Christe and Chris Grimes for introducing me to the ngModelController

You could try this directive to stop any invalid characters from being entered into an input field. (Update: this relies on the directive having explicit knowledge of the model, which is not ideal for reusability, see below for a re-usable example)

app.directive('isNumber', function () {
	return {
		require: 'ngModel',
		link: function (scope) {	
			scope.$watch('wks.number', function(newValue,oldValue) {
                var arr = String(newValue).split("");
                if (arr.length === 0) return;
                if (arr.length === 1 && (arr[0] == '-' || arr[0] === '.' )) return;
                if (arr.length === 2 && newValue === '-.') return;
                if (isNaN(newValue)) {
                    scope.wks.number = oldValue;
                }
            });
		}
	};
});

It also accounts for these scenarios:

1. Going from a non-empty valid string to an empty string
2. Negative values
3. Negative decimal values

I have created a jsFiddle here so you can see how it works.

UPDATE

Following Adam Thomas' feedback regarding not including model references directly inside a directive (which I also believe is the best approach) I have updated my jsFiddle to provide a method which does not rely on this.

The directive makes use of bi-directional binding of local scope to parent scope. The changes made to variables inside the directive will be reflected in the parent scope, and vice versa.

HTML:

<form ng-app="myapp" name="myform" novalidate> 
    <div ng-controller="Ctrl">
        <number-only-input input-value="wks.number" input-name="wks.name"/>
    </div>
</form>

Angular code:

var app = angular.module('myapp', []);

app.controller('Ctrl', function($scope) {
    $scope.wks =  {number: 1, name: 'testing'};
});
app.directive('numberOnlyInput', function () {
	return {
        restrict: 'EA',
        template: '<input name="{{inputName}}" ng-model="inputValue" />',
        scope: {
            inputValue: '=',
            inputName: '='
        },
		link: function (scope) {
            scope.$watch('inputValue', function(newValue,oldValue) {
                var arr = String(newValue).split("");
                if (arr.length === 0) return;
                if (arr.length === 1 && (arr[0] == '-' || arr[0] === '.' )) return;
                if (arr.length === 2 && newValue === '-.') return;
                if (isNaN(newValue)) {
                    scope.inputValue = oldValue;
                }
            });
		}
	};
});

First of all Big thanks to Adam thomas I used the same Adam's logic for this with a small modification to accept the decimal values.

Note: This will allow digits with only 2 decimal values

Here is my Working Example

HTML

<input type="text" ng-model="salary" valid-number />

Javascript

    var app = angular.module('myApp', []);
    
    app.controller('MainCtrl', function($scope) {
    });
    
    app.directive('validNumber', function() {
      return {
        require: '?ngModel',
        link: function(scope, element, attrs, ngModelCtrl) {
          if(!ngModelCtrl) {
            return; 
          }
    
          ngModelCtrl.$parsers.push(function(val) {
            if (angular.isUndefined(val)) {
                var val = '';
            }
            var clean = val.replace(/[^0-9\.]/g, '');
            var decimalCheck = clean.split('.');

            if(!angular.isUndefined(decimalCheck[1])) {
                decimalCheck[1] = decimalCheck[1].slice(0,2);
                clean =decimalCheck[0] + '.' + decimalCheck[1];
            }

            if (val !== clean) {
              ngModelCtrl.$setViewValue(clean);
              ngModelCtrl.$render();
            }
            return clean;
          });
    
          element.bind('keypress', function(event) {
            if(event.keyCode === 32) {
              event.preventDefault();
            }
          });
        }
      };
    });

Use the step tag to set the minimum changeable value to some decimal number:

e.g. step="0.01"

<input type="number" step="0.01" min="0" class="form-control" 
name="form_name" id="your_id" placeholder="Please Input a decimal number" required>

There is some documentation on it here:

http://blog.isotoma.com/2012/03/html5-input-typenumber-and-decimalsfloats-in-chrome/

DEMO - - jsFiddle

Directive

   .directive('onlyNum', function() {
      return function(scope, element, attrs) {

         var keyCode = [8,9,37,39,48,49,50,51,52,53,54,55,56,57,96,97,98,99,100,101,102,103,104,105,110];
          element.bind("keydown", function(event) {
            console.log($.inArray(event.which,keyCode));
            if($.inArray(event.which,keyCode) == -1) {
                scope.$apply(function(){
                    scope.$eval(attrs.onlyNum);
                    event.preventDefault();
                });
                event.preventDefault();
            }

        });
     };
  });

HTML

 <input type="number" only-num>

Note : Do not forget include jQuery with angular js

You could easily use the ng-pattern.

ng-pattern="/^[1-9][0-9]{0,2}(?:,?[0-9]{3}){0,3}(?:\.[0-9]{1,2})?$/"

There is an input number directive which I belive can do just what you want.

<input type="number"
   ng-model="{string}"
   [name="{string}"]
   [min="{string}"]
   [max="{string}"]
   [required]
   [ng-required="{string}"]
   [ng-minlength="{number}"]
   [ng-maxlength="{number}"]
   [ng-pattern="{string}"]
   [ng-change="{string}"]>

the official doc is here: http://docs.angularjs.org/api/ng.directive:input.number

HTML

 <input type="text" name="number" only-digits>

// Just type 123

  .directive('onlyDigits', function () {
    return {
      require: 'ngModel',
      restrict: 'A',
      link: function (scope, element, attr, ctrl) {
        function inputValue(val) {
          if (val) {
            var digits = val.replace(/[^0-9]/g, '');

            if (digits !== val) {
              ctrl.$setViewValue(digits);
              ctrl.$render();
            }
            return parseInt(digits,10);
          }
          return undefined;
        }            
        ctrl.$parsers.push(inputValue);
      }
    };

// type: 123 or 123.45

 .directive('onlyDigits', function () {
    return {
      require: 'ngModel',
      restrict: 'A',
      link: function (scope, element, attr, ctrl) {
        function inputValue(val) {
          if (val) {
            var digits = val.replace(/[^0-9.]/g, '');

            if (digits !== val) {
              ctrl.$setViewValue(digits);
              ctrl.$render();
            }
            return parseFloat(digits);
          }
          return undefined;
        }            
        ctrl.$parsers.push(inputValue);
      }
    };

I wanted a directive that could be limited in range by min and max attributes like so:

<input type="text" integer min="1" max="10" />

so I wrote the following:

.directive('integer', function() {
    return {
        restrict: 'A',
        require: '?ngModel',
        link: function(scope, elem, attr, ngModel) {
            if (!ngModel)
                return;
            
            function isValid(val) {
                if (val === "")
                    return true;

                var asInt = parseInt(val, 10);
                if (asInt === NaN || asInt.toString() !== val) {
                    return false;
                }

                var min = parseInt(attr.min);
                if (min !== NaN && asInt < min) {
                    return false;
                }
                
                var max = parseInt(attr.max);
                if (max !== NaN && max < asInt) {
                    return false;
                }

                return true;
            }

            var prev = scope.$eval(attr.ngModel);
            ngModel.$parsers.push(function (val) {
                // short-circuit infinite loop
                if (val === prev)
                    return val;
                
                if (!isValid(val)) {
                    ngModel.$setViewValue(prev);
                    ngModel.$render();
                    return prev;
                }

                prev = val;
                return val;
            });
        }
    };
});

Here's my really quick-n-dirty one:

<!-- HTML file -->
<html ng-app="num">
  <head></head>
  <body ng-controller="numCtrl">
    <form class="digits" name="digits" ng-submit="getGrades()" novalidate >
      <input type="text" placeholder="digits here plz" name="nums" ng-model="nums" required ng-pattern="/^(\d)+$/" />
      <p class="alert" ng-show="digits.nums.$error.pattern">Numbers only, please.</p> 
      <br>
      <input type="text" placeholder="txt here plz" name="alpha" ng-model="alpha" required ng-pattern="/^(\D)+$/" />
      <p class="alert" ng-show="digits.alpha.$error.pattern">Text only, please.</p>
      <br>
      <input class="btn" type="submit" value="Do it!" ng-disabled="!digits.$valid" />
    </form>
  </body>
</html>

// Javascript file
var app = angular.module('num', ['ngResource']);
app.controller('numCtrl', function($scope, $http){
  $scope.digits = {};
});

This requires you include the angular-resource library for persistent bindings to the fields for validation purposes.

Working example here

Works like a champ in 1.2.0-rc.3+. Modify the regex and you should be all set. Perhaps something like /^(\d|\.)+$/ ? As always, validate server-side when you're done.

This one seems the easiest to me: http://jsfiddle.net/thomporter/DwKZh/

(Code is not mine, I accidentally stumbled upon it)

    angular.module('myApp', []).directive('numbersOnly', function(){
       return {
         require: 'ngModel',
         link: function(scope, element, attrs, modelCtrl) {
           modelCtrl.$parsers.push(function (inputValue) {
               // this next if is necessary for when using ng-required on your input. 
               // In such cases, when a letter is typed first, this parser will be called
               // again, and the 2nd time, the value will be undefined
               if (inputValue == undefined) return '' 
               var transformedInput = inputValue.replace(/[^0-9]/g, ''); 
               if (transformedInput!=inputValue) {
                  modelCtrl.$setViewValue(transformedInput);
                  modelCtrl.$render();
               }         

               return transformedInput;         
           });
         }
       };
    });

I modified Alan's answer above to restrict the number to the specified min/max. If you enter a number outside the range, it will set the min or max value after 1500ms. If you clear the field completely, it will not set anything.

HTML:

<input type="text" ng-model="employee.age" min="18" max="99" valid-number />

Javascript:

var app = angular.module('myApp', []);

app.controller('MainCtrl', function($scope) {});

app.directive('validNumber', function($timeout) {
    return {
        require: '?ngModel',
        link: function(scope, element, attrs, ngModelCtrl) {
            if (!ngModelCtrl) {
                return;
            }

            var min = +attrs.min;
            var max = +attrs.max;
            var lastValue = null;
            var lastTimeout = null;
            var delay = 1500;

            ngModelCtrl.$parsers.push(function(val) {
                if (angular.isUndefined(val)) {
                    val = '';
                }            

                if (lastTimeout) {
                    $timeout.cancel(lastTimeout);
                }

                if (!lastValue) {
                    lastValue = ngModelCtrl.$modelValue;
                }

                if (val.length) {
                    var value = +val;
                    var cleaned = val.replace( /[^0-9]+/g, ''); 

                    // This has no non-numeric characters
                    if (val.length === cleaned.length) {
                        var clean = +cleaned;

                        if (clean < min) {
                            clean = min;
                        } else if (clean > max) {
                            clean = max;
                        }

                        if (value !== clean || value !== lastValue) {
                            lastTimeout = $timeout(function () {
                                lastValue = clean;
                                ngModelCtrl.$setViewValue(clean);
                                ngModelCtrl.$render();
                            }, delay);
                        }
                    // This has non-numeric characters, filter them out
                    } else {
                        ngModelCtrl.$setViewValue(lastValue);
                        ngModelCtrl.$render();
                    }
                }
                
                return lastValue;
            });

            element.bind('keypress', function(event) {
                if (event.keyCode === 32) {
                    event.preventDefault();
                }
            });

            element.on('$destroy', function () {
                element.unbind('keypress');
            });
        }
    };
});

I had a similar problem and update the input[type="number"] example on angular docs for works with decimals precision and I'm using this approach to solve it.

PS: A quick reminder is that the browsers supports the characters 'e' and 'E' in the input[type="number"], because that the keypress event is required.

angular.module('numfmt-error-module', [])
.directive('numbersOnly', function() {
  return {
    require: 'ngModel',
    scope: {
      precision: '@'
    },
    link: function(scope, element, attrs, modelCtrl) {
      var currencyDigitPrecision = scope.precision;
      
      var currencyDigitLengthIsInvalid = function(inputValue) {
        return countDecimalLength(inputValue) > currencyDigitPrecision;
      };
      
      var parseNumber = function(inputValue) {
        if (!inputValue) return null;
        inputValue.toString().match(/-?(\d+|\d+.\d+|.\d+)([eE][-+]?\d+)?/g).join('');
        var precisionNumber = Math.round(inputValue.toString() * 100) % 100;
        
        if (!!currencyDigitPrecision && currencyDigitLengthIsInvalid(inputValue)) {
          inputValue = inputValue.toFixed(currencyDigitPrecision);
          modelCtrl.$viewValue = inputValue;
        }
        return inputValue;
      };
      
      var countDecimalLength = function (number) { 
         var str = '' + number;
         var index = str.indexOf('.');
         if (index >= 0) {
           return str.length - index - 1;
         } else {
           return 0;
         }
      };
      
      element.on('keypress', function(evt) {
        var charCode, isACommaEventKeycode, isADotEventKeycode, isANumberEventKeycode;
        charCode = String.fromCharCode(evt.which || event.keyCode);
        isANumberEventKeycode = '0123456789'.indexOf(charCode) !== -1;
        isACommaEventKeycode = charCode === ',';
        isADotEventKeycode = charCode === '.';
        
        var forceRenderComponent = false;
        
        if (modelCtrl.$viewValue != null && !!currencyDigitPrecision) {
          forceRenderComponent = currencyDigitLengthIsInvalid(modelCtrl.$viewValue);
        }
       
        var isAnAcceptedCase = isANumberEventKeycode || isACommaEventKeycode || isADotEventKeycode;
        
        if (!isAnAcceptedCase) {
          evt.preventDefault();
        }
        
        if (forceRenderComponent) {
          modelCtrl.$render(modelCtrl.$viewValue);
        }

        return isAnAcceptedCase;
      });
      
      modelCtrl.$render = function(inputValue) {
        return element.val(parseNumber(inputValue));
      };
      
      modelCtrl.$parsers.push(function(inputValue) {

        if (!inputValue) {
          return inputValue;
        }

        var transformedInput;
        modelCtrl.$setValidity('number', true);
        transformedInput = parseNumber(inputValue);
        
        if (transformedInput !== inputValue) {
          
          modelCtrl.$viewValue = transformedInput;
          modelCtrl.$commitViewValue();
          modelCtrl.$render(transformedInput);
        }
        return transformedInput;
      });
    }
  };
});

And in your html you can use this approach

<input 
  type="number" 
  numbers-only 
  precision="2" 
  ng-model="model.value" 
  step="0.10" />

Here is the plunker with this snippet

Expanding from gordy's answer:

Good job btw. But it also allowed + in the front. This will remove it.

    scope.$watch('inputValue', function (newValue, oldValue) {
        var arr = String(newValue).split("");
        if (arr.length === 0) return;
        if (arr.length === 1 && (arr[0] == '-' || arr[0] === '.')) return;
        if (arr.length === 2 && newValue === '-.') return;
        if (isNaN(newValue)) {
            scope.inputValue = oldValue;
        }
        if (arr.length > 0) {
            if (arr[0] === "+") {
                scope.inputValue = oldValue;
            }
        }
    });

Here is a derivative that will also block the decimal point to be entered twice

HTML

    <input tabindex="1" type="text" placeholder="" name="salary" id="salary" data-ng-model="salary" numbers-only="numbers-only" required="required">

Angular

    var app = angular.module("myApp", []);

    app.directive('numbersOnly', function() {
    return {
	        require : 'ngModel', link : function(scope, element, attrs,  modelCtrl) {
		modelCtrl.$parsers.push(function(inputValue) {

			if (inputValue == undefined) {
				return ''; //If value is required
			}

			// Regular expression for everything but [.] and [1 - 10] (Replace all)
			var transformedInput = inputValue.replace(/[a-z!@#$%^&*()_+\-=\[\]{};':"\\|,<>\/?]/g, '');

			// Now to prevent duplicates of decimal point
			var arr = transformedInput.split('');

			count = 0; //decimal counter
			for ( var i = 0; i < arr.length; i++) {
				if (arr[i] == '.') {
					count++; //  how many do we have? increment
				}
			}

			// if we have more than 1 decimal point, delete and leave only one at the end
			while (count > 1) {
				for ( var i = 0; i < arr.length; i++) {
					if (arr[i] == '.') {
						arr[i] = '';
						count = 0;
						break;
					}
				}
			}

			// convert the array back to string by relacing the commas
			transformedInput = arr.toString().replace(/,/g, '');

			if (transformedInput != inputValue) {
				modelCtrl.$setViewValue(transformedInput);
				modelCtrl.$render();
			}

			return transformedInput;
		});
	}
};
});

Extending Adam Thomas answer you can easily make this directive more generic by adding input argument with custom regexp:

var app = angular.module('myApp', []);

app.controller('MainCtrl', function($scope) {
});

app.directive('validInput', function() {
  return {
    require: '?ngModel',
    scope: {
      "inputPattern": '@'
    },
    link: function(scope, element, attrs, ngModelCtrl) {

      var regexp = null;

      if (scope.inputPattern !== undefined) {
        regexp = new RegExp(scope.inputPattern, "g");
      }

      if(!ngModelCtrl) {
        return;
      }

      ngModelCtrl.$parsers.push(function(val) {
        if (regexp) {
          var clean = val.replace(regexp, '');
          if (val !== clean) {
            ngModelCtrl.$setViewValue(clean);
            ngModelCtrl.$render();
          }
          return clean;
        }
        else {
          return val;
        }

      });

      element.bind('keypress', function(event) {
        if(event.keyCode === 32) {
          event.preventDefault();
        }
      });
    }
}});

HTML

<input type="text" ng-model="employee.age" valid-input  
       input-pattern="[^0-9]+" placeholder="Enter an age" />
</label>

Live on CodePen

Please check out my component that will help you to allow only a particular data type. Currently supporting integer, decimal, string and time(HH:MM).

• string - String is allowed with optional max length
• integer - Integer only allowed with optional max value
• decimal - Decimal only allowed with optional decimal points and max value (by default 2 decimal points)
• time - 24 hr Time format(HH:MM) only allowed

https://github.com/ksnimmy/txDataType

Hope that helps.

DECIMAL

directive('decimal', function() {
                return {
                    require: 'ngModel',
                    restrict: 'A',
                    link: function(scope, element, attr, ctrl) {
                        function inputValue(val) {
                            if (val) {
                                var digits = val.replace(/[^0-9.]/g, '');
    
                                if (digits.split('.').length > 2) {
                                    digits = digits.substring(0, digits.length - 1);
                                }
    
                                if (digits !== val) {
                                    ctrl.$setViewValue(digits);
                                    ctrl.$render();
                                }
                                return parseFloat(digits);
                            }
                            return "";
                        }
                        ctrl.$parsers.push(inputValue);
                    }
                };
            });

DIGITS

directive('entero', function() {
            return {
                require: 'ngModel',
                restrict: 'A',
                link: function(scope, element, attr, ctrl) {
                    function inputValue(val) {
                        if (val) {
                            var value = val + ''; //convert to string
                            var digits = value.replace(/[^0-9]/g, '');

                            if (digits !== value) {
                                ctrl.$setViewValue(digits);
                                ctrl.$render();
                            }
                            return parseInt(digits);
                        }
                        return "";
                    }
                    ctrl.$parsers.push(inputValue);
                }
            };
        });

angular directives for validate numbers