You can use this onchange script to limit the options in the list collector in Service Catalog.
varName will be the name of list collector and maxSelections will be the maximum number options.

function onChange(control, oldValue, newValue, isLoading) {
var varName = ‘users’;
var maxSelections = 20;

$$(‘#’ + varName + ‘_select_0 option’)
.each(function(elem,index){
if(index >= maxSelections)
elem.remove();
});
}

Sure, check out the post above for the newly-added Service Portal version of this script. You’ll need to have 2 separate client scripts…each one running for a different UI type (Desktop and Mobile).

Thank you for the great post. I used this script it on one of my variable and it worked fine in the servicenow native UI. But, we are on Helsinki and the business users are using service portal to log their request. List collector behave differently on service portal. By different I mean, their is no right and left slush bucket so your script doesn’t work on service portal. Can you please provide a modified version of your script that could work even on portal list collector variable?

Thank you!

Unfortunately no. This is the big challenge with service portal at the moment. Lots of flash and marketing hype, but really limited API and client scripting flexibility.

You can disregard that warning. The script should work fine regardless.

Cool, will do that… thanks so much for the reply…!!! Will reply back once we figure out what we did wrong… :-)

I just tested this on a ServiceNow demo instance and it worked perfectly there. I just pasted directly into a new ‘onChange’ catalog client script, changed the name of the variable to match in the script, and ran it. You should try to see if you can get it working on a test in demo. My guess is that there’s something else in your environment causing issues.