Javascript simple question

**astral** · 07-03-2011

Sorry I know this place is mainly for C. But I don't really want to have to register to another site for this JS question. (I'm sure a lot of you have dealt with websites anyway

)

This question is pretty simple, but I just can't figure out why the FOR loop breaks. To me it seems like a bug. It simply breaks after 1 iteration.

I created a dummie page, for you to see. Simply save it as a .html and run it

Code:

<html><head><script type="text/javascript">

function validateForm()
{

var fields = new Array;
var fields =[
document.getElementById("one"),
document.getElementById("two"),
document.getElementById("three")];

  for (var i = 0; i < parseInt(fields.length); i++) {
    alert(i);

    if ( fields[i].value == "" ) {
      alert("Field" + (i+1) + " has no value");   
    }
 
  }

}
</script></head><body>

<form name="form1">
Field 1 enter: <input type="text" id="one"> <br />
Field 2 enter: <input type="text" name="two"> <br />
Field 3 etner: <input type="text" name="three"> <br /><br />

<input type="button" onclick="validateForm()" value="Submit" />

</form></body></html>

The error occurs on fields[i].value .. The error is the var i
You see, if you replace i with 0: fields[0].value, it will successfully loop 3 times.
I just don't understand why using that variable, fails?

I tried so many things, moving the script to bottom of page, converting value of i to a char, etc. I may of missed something, but if you take a quick look maybe you know this problem. (I know I can resort to doing multiple IF statement, I just want to know why this logical loop doesn't work)

**whiteflags** · 07-03-2011

I don't think i is the problem, from here it looks like some elements of your form are null. I noticed:

Code:

Field 1 enter: <input type="text" id="one"> <br />
Field 2 enter: <input type="text" name="two"> <br />
Field 3 etner: <input type="text" name="three"> <br /><br />

You should use id for all of these. When I changed it, getElementById worked. I think there is something like getElementByName, but you need to pick one or the other.

**astral** · 07-03-2011

Originally Posted by whiteflags

I don't think i is the problem, from here it looks like some elements of your form are null. I noticed:

Code:

Field 1 enter: <input type="text" id="one"> <br />
Field 2 enter: <input type="text" name="two"> <br />
Field 3 etner: <input type="text" name="three"> <br /><br />

You should use id for all of these. When I changed it, getElementById worked. I think there is something like getElementByName, but you need to pick one or the other.

LOL, I'm such a dumbass. I never even noticed for a second, that they were "name" instead of "id", spent the whole of yesterday and today googling javascript var bugs. -___-

**whiteflags** · 07-03-2011

Happens to the best of us.

**Elysia** · 07-03-2011

I just thought I'd mention there is a Techboard for programming related questions for languages of non-existing forums.

**laserlight** · 07-03-2011

Thread moved to Tech board.

**CornedBee** · 07-04-2011

Why do you use parseInt on the length property of an array? It's already numeric.

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