how to validate a textarea using javascript

Question

I want to check a textarea whether it is empty or not. For this I write the following code:

function validateForm(theForm) {
    var problem_desc = document.getElementById("problem_desc");

    if (problem_desc.value == '') {
        alert("Please Write Problem Description");
        return false;
    } else {
        return true;
    }
}

For the first time it is working fine. But If I remove the text from the textarea the above function is returning true value i.e., it is assuming the previous text I've entered into the textbox. Can anybody kindly tell me where is the problem?

It seems to work just fine: jsfiddle.net/Blender/XHUZ4

Blender
– Blender

2012-09-28 07:29:26 +00:00
Commented Sep 28, 2012 at 7:29 — Blender
– Blender, Commented Sep 28, 2012 at 7:29
Maybe relevant to show your HTML

Alex R.
– Alex R.

2012-09-28 07:33:41 +00:00
Commented Sep 28, 2012 at 7:33 — Alex R.
– Alex R., Commented Sep 28, 2012 at 7:33

Praveen Kumar Purushothaman · Accepted Answer · 2012-09-28 07:32:11Z

4

I am getting it correctly. This is what I did.

Click on validate, it said Please Write Problem Description.
Write something and click. Nothing happened.
Remove the text. Click on validate, it said Please Write Problem Description.

Note: Use a trim function to eliminate empty spaces.

Code:

function validateForm(theForm) {
    var problem_desc = document.getElementById("problem_desc");

    if ($.trim(problem_desc.value) == '') {
        alert("Please Write Problem Description");
        return false;
    } else {
        return true;
    }
}

Demo: http://jsfiddle.net/TZGPM/1/ (Checks for Whitespaces too!)

answered Sep 28, 2012 at 7:32

Praveen Kumar Purushothaman

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2 Comments

user1407310 Over a year ago

Yor are right @Praveen Kumar. I use the trim() method. But still it is not working. My trim() method is given below function trim(s) { return s.replace( /^\s*/, "" ).replace( /\s*$/, "" ); }

Praveen Kumar Purushothaman Over a year ago

@user1407310 Is it possible for you to use jQuery?

Pranay Rana · Accepted Answer · 2012-09-28 07:30:07Z

3

Do check for white space in the value like this

if (problem_desc.value.match (/\S/)) { ... }

or other way check for length

 problem_desc.value.length == 0;

answered Sep 28, 2012 at 7:30

Pranay Rana

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Comments

Netham · Accepted Answer · 2016-10-10 15:38:48Z

0

Remove spaces and calculate length of the value attribute.

function validateForm(theForm) {
    var problem_desc = document.getElementById("problem_desc");

    if (problem_desc.value.replace(/ /g,'').length) {
       return true;
    } else {
       alert("Please Write Problem Description");
       return false;
    }
}

<textarea id="problem_desc"></textarea>
<button onclick="validateForm()">Validate</button>

answered Oct 10, 2016 at 15:38

Netham

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how to validate a textarea using javascript

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Code:

Demo: http://jsfiddle.net/TZGPM/1/ (Checks for Whitespaces too!)

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Code:

Demo: http://jsfiddle.net/TZGPM/1/ (Checks for Whitespaces too!)

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