Javascript dynamic field validation

@nac20Jul 28.2008

I’ve a page which renders a group of input fields x times depending on the user’s choice of x from a dropdown (1-6).
I want to validate their input (mandatory fields) so I do this using Javascript with a function IsEmpty to which I pass the field name and text to display in an alert.
I can’t concatenate a string with the field name (e.g. lastname_ + ’01’) as I receive an error that object doesn’t exist.
Can someone please explain how I can perform validation on the dynamic fields?

Thanks in advance,

Alan

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JavaScript

@KorJul 28.2008 — #We need to see the code, so far.

@nac20authorJul 28.2008 — #Please see a static version of the code below which works, simplified to show one input field called txtFirstName.

My dynamic page containing the form 'frmStep1' will contain 1-6 instances, i.e. txtFirstName_0 - txtFirstName_5 depending on user input from a previous page

so I want to be able to create a loop in the Javascript to check the input accordingly, I'm guessing I therefore need to pass in the number as a parameter to checkInput.

I tried lots of combinations to get this working and kept hitting errors stating that the object didn't exist.

<form ... name="frmStep1" onSubmit="return checkInput();">

</form>

function isEmpty(formElement, message) {

formElement.value = trim(formElement.value);

_isEmpty = false;
  if (formElement.value == '') {
   _isEmpty = true;
   alert(message);
   formElement.focus();
  }
 
  return _isEmpty;

}

function checkInput()

{

with (window.document.frmStep1) {

if (isEmpty(txtFirstName, 'Enter first name')) {

return false;

} else {

return true;

}

}

}

@KorJul 28.2008 — #

<i>
 </i>&lt;form name="frmStep1" onsubmit="return checkInput(this);"&gt;

<i>
 </i>&lt;script type="text/javascript"&gt;
 function isEmpty(formElement, message){
 formElement.value = trim(formElement.value);
 var _isEmpty = false;
 if (formElement.value == ''){
 _isEmpty = true;
 alert(message);
 formElement.focus();
 }
 return _isEmpty;
 }
 function checkInput(f){
 var i=0, t;
 while(t=f['txtFirstName_'+[i++]]){
 if(isEmpty(t,'Please fill all the required fields!')){return false}
 }
 }
 &lt;/script&gt;

Javascript dynamic field validation

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