Javascript validation

[mckeegan375]

Hi All!

 

I was hoping someone could help me with some simple JS form validation which involves a loop.

 

So far, i have the following:

 

<SCRIPT language=JavaScript>

function validateForm()

{

 

var a = document.getElementsById('totalpayment');

var b = document.getElementsById('netpay');

 

for(var k=0;k<b.length;k++){

var c = a[k]

var d = b[k]

 

if (c.value > d.value)

{

alert("Total payment cannot be greater than net pay");

return false;

}

}

 

}

</script> 

 

 

My form has a loop which pulls data from a mysql database and it contains the fields 'totalpayment' and 'netpay' yet the validation does not display the alert if the total payment entered is greater than the net pay.

 

Any help would be much appreciated.

 

Cheers

Andy

[joe92]

 var a = document.getElementsById('totalpayment'); //it's getElementById, notice the lack of s
var b = document.getElementsById('netpay'); 

 

This is invalid. You cannot grab multiple elements by ID. What you need to use is getElementsByClassName and attach the relevant class to the elements you wish to check.

 

Hope that helps you,

Joe

[Adam]

getElementsByClassName() is not supported in IE before version 9, so you need to define a manual implementation when it doesn't exist as a back-up.

[joe92]

That's a good point, one that I should have remembered to mention.

 

http://lawrence.ecorp.net/inet/samples/js-getelementsbyclassname.shtml

 

The one in the link above works like a charm.

 

Joe

[mckeegan375]

Thanks for all your help guys!

 

Joe, i used the link you posted for my solution

 

Cheers

Andy