Why does the html input with type "number" allow the letter 'e' to be entered in the field?
HtmlInputNumbersHtml Problem Overview
I have the following html5 input element:
<input type="number">
Why does this input allow for the character 'e' to be entered in the input field? No other alphabet character is able to be entered (as expected)
Using chrome v. 44.0.2403.107
Example below to see what I mean.
<input type="number">
Html Solutions
Solution 1 - Html
Because that's exactly how the spec says it should work. The number input can accept floating-point numbers, including negative symbols and the e
or E
character (where the exponent is the number after the e
or E
):
> A floating-point number consists of the following parts, in exactly
> the following order:
>
> 1. Optionally, the first character may be a "-
" character.
> 2. One or more characters in the range "0—9
".
> 3. Optionally, the following parts, in exactly the following order:
> 1. a ".
" character
> 2. one or more characters in the range "0—9
"
> 4. Optionally, the following parts, in exactly the following order:
> 1. a "e
" character or "E
" character
> 2. optionally, a "-
" character or "+
" character
> 3. One or more characters in the range "0—9
".
Solution 2 - Html
We can make it So simple like below
<input type="number" onkeydown="javascript: return event.keyCode == 69 ? false : true" />
Updated Answer
we can make it even more simple as @88 MPG suggests
<input type="number" onkeydown="return event.keyCode !== 69" />
Solution 3 - Html
The best way to force the use of a number composed of digits only:
<input type="number" onkeydown="javascript: return ['Backspace','Delete','ArrowLeft','ArrowRight'].includes(event.code) ? true : !isNaN(Number(event.key)) && event.code!=='Space'" />
this avoids 'e', '-', '+', '.' ... all characters that are not numbers !
To allow number keys only, convert to number with Number
function. If this is not a number, the result is NaN :
> isNaN(Number(event.key))
but accept Backspace, Delete, Arrow left, Arrow right : > ['Backspace','Delete','ArrowLeft','ArrowRight'].includes(event.code)
This is for Firefox which allows spaces : > event.code!=='Space'
Solution 4 - Html
HTML input number type allows "e/E" because "e" stands for exponential which is a numeric symbol.
Example 200000 can also be written as 2e5. I hope this helps thank you for the question.
Solution 5 - Html
<input type="number" onkeydown="return FilterInput(event)" onpaste="handlePaste(event)" >
function FilterInput(event) {
var keyCode = ('which' in event) ? event.which : event.keyCode;
isNotWanted = (keyCode == 69 || keyCode == 101);
return !isNotWanted;
};
function handlePaste (e) {
var clipboardData, pastedData;
// Get pasted data via clipboard API
clipboardData = e.clipboardData || window.clipboardData;
pastedData = clipboardData.getData('Text').toUpperCase();
if(pastedData.indexOf('E')>-1) {
//alert('found an E');
e.stopPropagation();
e.preventDefault();
}
};
Solution 6 - Html
A simple solution to exclude everything but integer numbers
<input
type="number"
min="1"
step="1"
onkeypress="return event.keyCode === 8 || event.charCode >= 48 && event.charCode <= 57">
This solution does not prevent copy and pasting (including the letter 'e').
Solution 7 - Html
To hide both letter e
and minus sign -
just go for:
onkeydown="return event.keyCode !== 69 && event.keyCode !== 189"
Solution 8 - Html
Using angular, You can do this to restrict to enter e,+,-,E
<input type="number" (keypress)="numericOnly($event)"/>
numericOnly(event): boolean { // restrict e,+,-,E characters in input type number
debugger
const charCode = (event.which) ? event.which : event.keyCode;
if (charCode == 101 || charCode == 69 || charCode == 45 || charCode == 43) {
return false;
}
return true;
}
Solution 9 - Html
The E stands for the exponent, and it is used to shorten long numbers. Since the input is a math input and exponents are in math to shorten great numbers, so that's why there is an E.
It is displayed like this: 4e.
Solution 10 - Html
Angular; with IDE keyCode deprecated warning
Functionally the same as rinku's answer but with IDE warning prevention
numericOnly(event): boolean {
// noinspection JSDeprecatedSymbols
const charCode = (event.which) ? event.which : event.key || event.keyCode; // keyCode is deprecated but needed for some browsers
return !(charCode === 101 || charCode === 69 || charCode === 45 || charCode === 43);
}
Solution 11 - Html
The above solutions work in regular html only. For reactJS I would suggest you to do this instead
<input type="number" onKeyDown={(e) =>["e", "E", "+", "-"].includes(e.key) && e.preventDefault()} >
Solution 12 - Html
Simple and standard solution : In Angular/ Js/ Ts you can use regular expression to restrict any input key.
HTML: <input type="text" name="input1" (keypress)="numericOnly($event)" />
TS:
numericPattern = /^[0-9]*$/;
numericOnly(event){
return this.numericPattern.test(event.key);
}
Solution 13 - Html
if you hit a key and its computer language equivalent is 69 it won't type it
<input
type="number"
onkeydown="return event.keyCode !== 69"
/>