Checking length of form field

[W8 4me]

Hi,

I'm trying to change the border colour of any text input form field that has a length of more than zero. So far I've been trying this but it doesn't work...

<script type="text/javascript">
var notempty = document.getElementsByTagName(input).value;
if (notempty.value.length > 0) { document.getElementsByTagName(input).style.borderColor="red"; }
else { document.getElementsByTagName(input).style.borderColor="transparent"; }
</script>

I don't know if it's a syntax thing, or if I'm just plain doing it wrong.

I'm trying to actually learn and understand Javascript so if you could help me to adapt this code rather than giving me a more efficient way of doing this then that'd be great.

cheers guys

[rtrethewey]

Try:

<script type="text/javascript">
var notempty = document.getElementsByTagName('input');  // Get all of the <input> tags in the array 'notempty'
for (i=0; i<notempty.length; i++) {  // Loop through the entire array of <input> tags
  if (notempty[i].type == 'text') {  // Only check type="text" <input> tags
    if (notempty[i].value.length > 0) { notempty[i].style.borderColor="red"; }
     else { notempty[i].style.borderColor="transparent"; }
  } // endif type='text'
 } // end for i
</script>

[W8 4me]

Hi sorry it's not working. I tried to understand the code - does 'i' stand for integer?

I don't understand why my original code didn't work - it seems logically set out. odd...

[Logic Ali]

I don't understand why my original code didn't work

Use the error console.

Hi sorry it's not working.

Such a block of inline code must me positioned below the elements to which it refers.

[W8 4me]

Hi thanks.

I put rtrethewey's code in a function called checkme() and then called it in the input tag as an onkeyup.

rtrethewey, I've just learnt about loops on codecademy.com, but was wondering why we need a loop for this?

Also why won't the script work without needing to be in a function/called from the onkeyup?

(i=0; i<notempty.length; i++) - please can you explain this line? I've got loops sort of in my head, but using numbers.

thanks again