How to read line by line of a text area HTML tag

I have a text area where each line contains Integer value like follows

      1234
      4321
     123445

I want to check if the user has really enetered valid values and not some funny values like follows

      1234,
      987l;

For that I need to read line by line of text area and validate that. How can i read line by line of a text area using javascript?

Try this.

var lines = $('textarea').val().split('\n');
for(var i = 0;i < lines.length;i++){
    //code here using lines[i] which will give you each line
}

This works without needing jQuery:

var textArea = document.getElementById("my-text-area");
var arrayOfLines = textArea.value.split("\n"); // arrayOfLines is array where every element is string of one line

This would give you all valid numeric values in lines. You can change the loop to validate, strip out invalid characters, etc - whichever you want.

var lines = [];
$('#my_textarea_selector').val().split("\n").each(function ()
{
    if (parseInt($(this) != 'NaN')
        lines[] = parseInt($(this));
}

###Two options: no JQuery required, or JQuery version

###No JQuery (or anything else required)

var textArea = document.getElementById('myTextAreaId');
var lines = textArea.value.split('\n');    // lines is an array of strings

// Loop through all lines
for (var j = 0; j < lines.length; j++) {
  console.log('Line ' + j + ' is ' + lines[j])
}

###JQuery version var lines = $('#myTextAreaId').val().split('\n'); // lines is an array of strings

// Loop through all lines
for (var j = 0; j < lines.length; j++) {
  console.log('Line ' + j + ' is ' + lines[j])
}

---

Side note, if you prefer forEach a sample loop is

lines.forEach(function(line) {
  console.log('Line is ' + line)
})

A simple regex should be efficent to check your textarea:

/\s*\d+\s*\n/g.test(text) ? "OK" : "KO"

A simplifyied Function could be like this:

function fetch (el_id, dest_id){
var dest = document.getElementById(dest_id),
texta = document.getElementById(el_id),
val = texta.value.replace(/\n\r/g,"<br />").replace(/\n/g,"<br />");
dest.innerHTML = val;
}

for the html code below (as an example only):

<textarea  id="targetted_textarea" rows="6" cols="60">
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  </textarea>
  <button onclick="fetch('targetted_textarea','destination')" id="convert">Convert</button>

<div id="destination">Had not been fetched yet click convert to fetch ..!</div>