client side form validation Array

styleBunny · Mar 28, 2005

Hi All,

I have this function to validate, whether a users has made a selection from a multiple selection list box.

Code:

<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<title>Untitled Document</title>
<script language="javascript">

function validateContactForm(form) {
		if (form.foo.length == 0) { 
			alert('Please select.'); 
			return false;
		}
}

</script>
</head>

<body>
<form name="contact" method="post" onSubmit="return validateContactForm(this);">

<select name="foo[]" size="5" multiple> 
	<option value="apples">Apples</option>
	<option value="oranges">Oranges</option>
	<option value="pears">Pears</option>
	<option value="grapes">Grapes</option>
	<option value="mangos">Mangos</option>
</select>
<br>
<input type="submit" name="btnSubmit" value="Submit"> <input type="reset" name="btnReset" value="Clear">
</form>
</body>
</html>

I can get the length value returned when the array is static, but when its a dynamic array, created inside a form I haven had any luck!

Thanks for looking,
sb.

trollacious · Mar 28, 2005

I know that PHP uses [] for element arrays, but it's not valid HTML according to W3C, the people who write the standards.

Try this with what you have:

Code:

function validateContactForm(thisform)
{
var numselected = 0;
var selection = thisform.elements['foo[]'];
for (var si=0;si<selection.options.length;si++)
  {
  if (selection.options[si].selected)
    {
    numselected++;
    }
  }

if (numselected == 0)
  {
  alert('Please select at least one item.');
  return false;
  }
return true;
}

Lee

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client side form validation Array

styleBunny

Technical User

trollacious

Programmer

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