Javascript function not triggerred

Question

I have a JavaScript function in my head part of my HTML

<script>
   function validateForm() 
   {
     var apple = document.getElementById('apple').value;
     var err = 0;
     if (isNaN(apple)) {
        err += 1;
    }
    if (err != 0) {
        alert('Please check your input!');
        return false;
    } 
    else 
        return true; 
}
</script>

The form is shown below:

 <form name="orderForm" onSubmit="return validateForm();" method="post">  
    <div class="input-control text span5">
          <input class="span5" type="text" placeholder="Each @ $4.9" id="apple" name="apple" onChange='checkApple(this.value)'>
    </div>
  </form>

all brackets are completed and there is no typo.

When I submit the form with non numerical values, the form still gets submitted instead of error. May I know what's wrong with this ?

Have you tried not using JavaScript? <input type="number" .../> — Niet the Dark Absol
– Niet the Dark Absol, Commented Aug 30, 2013 at 12:19

tckmn · Accepted Answer · 2013-08-30 12:25:26Z

1

You need to accept an event:

function validateForm(e) {

And prevent it:

if (err != 0) {
    e.preventDefault()
    ...

On an unrelated note, I would suggest that you restructure your code so it is less complicated, like:

var apple = document.getElementById('apple').value;
if (isNaN(apple)) {
    ...

No need for an err variable.

edited Aug 30, 2013 at 12:25

answered Aug 30, 2013 at 12:20

tckmn

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2 Comments

Niet the Dark Absol Over a year ago

Wait what? Since when was "some string" not NaN (ie. a number)?

tckmn Over a year ago

@Kolink Fixed (again)

sd1sd1 · Accepted Answer · 2013-08-30 12:19:39Z

0

you must have input type="submit" or a button type="submit" in order for the onsubmit to trigger

answered Aug 30, 2013 at 12:19

sd1sd1

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1 Comment

Devang Rathod Over a year ago

Without it also submitted.

Barry Beerman · Accepted Answer · 2013-08-30 12:22:55Z

0

If your trying to perform a check for whether the input is a number, this may work:

function validateForm() 
{
     var apple = document.getElementById('apple').value;
     var err = 0;
     if (!isNaN(parseFloat(apple)) && isFinite(apple)) {
        err += 1;
     }
     if (err != 0) {
        alert('Please check your input!');
        return false;
     } 
     else 
        return true; 
}

answered Aug 30, 2013 at 12:22

Barry Beerman

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