Validating Dropdown Lists

Question: In a dropdown list, I want to make sure that a choice is selected other than the first one (which asks the user to choose a value), what attributes of the dropdown list do I use to validate this?

Answer: The easiest way to do this is to give the first entry a value of blank and assign non-blank values to the entries that you want selected from. eg:

<form name="myform">
<select name="sel" size="1">
<option value=" ">Please select an option below</option>
<option value="1">Option One</option>
<option value="2">Option Two</option>

Now in your validation you test if the field is blank.

if (document.myform.sel.options[ document.myform.sel.options.selectedIndex ].value == " ")
alert("You must choose an option");

Just substitute the correct names for the form and selection box that you are validating.


This article written by Stephen Chapman, Felgall Pty Ltd.

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