OnChange Catalog Client Script Nuance

My friend Peter from Down Under sent me a great tip the other day about an issue he had with an onChange catalog client script. It’s something that I wasn’t aware of which goes to show you that there’s always something new that you can learn :). Hopefully this tip keeps someone from having to bang their head against a wall for a few hours.
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function onChange(control,oldValue,newValue,isLoading){
   if(!isLoading) {
      var newValueString = String(newValue);
      switch(newValueString ) {
         case 'Option One':
         case 'Option Two':

It’s a catalogue client script that shows/hides form inputs based on the
option that is chosen. The tricky thing, and the thing that stumped us for
quite a while, is that the system variables provided by the OnChange
function are objects and not strings. So the String(newValue) is critical
or the case statement will fail.

To summarize: OnChange Catalog Client Scripts work differently than regular OnChange client scripts. In order to use the ‘newValue’ and ‘oldValue’ parameters for comparison purposes they need to be converted into a different variable type. The easiest way to do this is to use ‘String(newValue)’ or ‘newValue.toString()’.

Date Posted:

January 6, 2010

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  1. Peter Oneppo April 17, 2011 at 3:10 pm

    Somewhat along these lines is a “feature” I discovered with pushing sys_ids into an array while looping through a GlideRecord. Here’s what I had at first:

    var ids = new Array();
    var gr = new GlideRecord("incident");
    while(gr.next()) {

    When I was done, every value in the array was the same. They were all equal to the sys_id of the last Glide Record that was found. This is because “gr.sys_id” is an object, so what you end up with is a bunch of pointers in your array all pointing to gr.sys_id, which contains that last sys_id.

    I solved the problem by changing my code to this:


    This should work too:


    You might need a “new” before “String”.

    I hope that helps someone out there!

    • Mark Stanger April 18, 2011 at 12:10 am

      Thanks Peter,

      I remember this giving me fits when I first came across it. Good tip!

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