[thelist] js testing for empty fields
Ben Dyer
ben_dyer at imaginuity.com
Thu Feb 13 15:28:01 CST 2003
At 03:05 PM 2/13/2003, you wrote:
> > you could also just check for:
> >
> > if(myForm.elements['myField'].value) { doSomething() }
> >
> > assuming your form was anything but boolean
>
>Well, if the user enters 0 (zero) then the above if expression would
>evaluate as false in JavaScript, even though the user indeed entered data,
>so I wouldn't actually recommend this. :)
Actually, I don't think that's true. I just whipped up a quick test.
<script language="JavaScript">
<!--
function test() {
if (!document.forms[0].elements[0].value) {
alert("test IS false");
return false;
} else {
alert("test IS true");
return false;
}
}
//-->
</script>
<form method="post" action="anything.html" onsubmit="return test()">
<input type="text" name="testField" id="testField" size="15" value="" /><br />
<input type="submit" name="Submit" value="Submit" />
</form>
When you submit, the only time the alert "test IS false" came up was when
there was no value in the text field. A value of "0" correctly returned
the "test IS true" box, as did anything else I entered: "1", "false", "Rei
Ayanami", etc.
I only tested IE6/W2K, but I've never heard of it being the case to return
false when the form field value is 0. Perhaps I'm misunderstanding what
you're suggesting.
--Ben
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