Question

I’ve got some javascript that I want to attach to forms and to HTML web resources in MS dynamics CRM 2011. It needs the Xrm object, which is available either directly when in a form context or via window.top.Xrm when in a HTML web resource.

I thought I’d write a quick function to check if Xrm is defined or not, allowing me to work out whether I’m running in the form or in a HTML web resource. As a starting point, because I’m really new to javascript, I wrote this code to check for Xrm being present and show a message.

alert('Running'); 
if(Xrm) { alert('Yup'); } else { alert('Nope'); }
alert('Done'); 

However, this doesn’t work and I don’t understand why. When it runs within a form event, such as form load, Xrm is present and I see the alerts “Running”, “Yup” and “Done”. However, when running in a HTML web resource, where Xrm is not directly available, I see the “Running” alert but the javascript just stops on the next line.

Please help!

Answer 1

When Xrm is not defined your code will raise an exception ReferenceError: Xrm is not defined and halt the execution of the rest of your Javascript. To check for the existence of a variable you should use:

if (typeof Xrm !== 'undefined') { alert('Yup'); } else { alert('Nope'); }