Integer Validation using javascript

Question

I am using the following code for validating whether the field is empty or not.

<label>Sermon Title</label>
<input class="text-input small-input" type="text" id="sermon_title" name="sermon_title" />
<span id="stitlespansuccess" class="input-notification success png_bg" style="display: none;"></span>
<span id="stitlespanerror" class="input-notification error png_bg" style="display: none;"></span>

    $(document).ready(function () {  
        var submit           = false;
        $('#sermon_title').bind('focusout', function() {
            var sermon_title       = $('#sermon_title').val();
            var pid       = $('#preacher').val();
            if( sermon_title == "") {
                $('#stitlespanerror').html("Title required");
                $('#stitlespanerror').show();
                $('#stitlespansuccess').hide();
                submit = false;
            }
            else
            {
                $('#stitlespanerror').hide();
                $.post("<?= site_url('admin/sermons/uniquetitle/') ?>", { sermon_title: sermon_title,pid:pid },
                function(data){
                    if( "success" == data.trim() ) {
                        $('#stitlespansuccess').show();
                        submit = true;
                    }
                    else
                    {
                        $('#stitlespansuccess').hide();
                        $('#stitlespanerror').html("Title already taken");
                        $('#stitlespanerror').show();
                        submit = false;
                    }
                });
            }
        });
});

I want to check whether the value is integer or not.

Ido Green · Accepted Answer · 2012-01-02 08:23:12Z

4

This is the correct function to check for integers (e.g. some like: 1.0 etc')

function is_int(value){ 
  if((parseFloat(value) == parseInt(value)) && !isNaN(value)){
    return true;
  } else { 
    return false;
  } 
}

answered Jan 2, 2012 at 8:23

Ido Green

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2 Comments

nnnnnn Over a year ago

Which can be simplified to a one-line function: return parseFloat(value) === parseInt(value) && !isNan(value);

nnnnnn Over a year ago

P.S. Note that the above thinks that "012" is not an integer...don't use parseInt() without specifying the radix: parseInt(value,10)

asitha · Accepted Answer · 2012-01-02 08:06:20Z

2

try this

if (isNaN(value))

hope it will work

answered Jan 2, 2012 at 8:06

asitha

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Comments

nnnnnn · Accepted Answer · 2012-01-02 09:44:23Z

0

You want to check whether what value is an integer? Surely not Sermon Title? There's a lot of code there that doesn't seem at all related to your question.

Anyway, assuming you want to validate a user input value to be sure it is an integer, you can convert it to a number and then test whether the number is equal the same number rounded down:

function isInteger(val) {
   var n = +val;    // convert with unary plus operator
   return val != "" && n === Math.floor(n);
}

Note that an empty string will convert to 0, hence the test that val is not an empty string.

Potential problem: The above would treat "1.000" as an integer - is that acceptable?

If you don't want the user to enter a decimal point another way to approach it is to validate with a regex, making sure that only digits have been entered (no decimal point):

function isInteger(val) {
   return /^-?\d+$/.test(val);
}

If you need to restrict it to a certain number of digits this is easy with regex:

// e.g., max four digits, optional minus sign:
return /^-?\d{1,4}$/.test(val);

(Note: `isNaN() is "broken".)

answered Jan 2, 2012 at 9:44

nnnnnn

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1 Comment

nnnnnn Over a year ago

Sure. My point was if you provide an example try to have it relate to the question at hand.

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