How to handle getElementById return Null

Question

On our web application there are many pages. Some of them contain element \"Ribbon.ListForm.Display.Manage.Workflows-Medium\" while some pages not.

I would like to use s

Answer 1

Since the question is tagged with jQuery:

$('#Ribbon\.ListForm\.Display\.Manage,#Ribbon\.ListForm\.Display\.Manage\.Workflows-Medium,#Ribbon\.ListForm\.Display\.Manage\.CheckOut-Large')
    .filter(function() {
        return this.value == '';
    })
    .hide();

First, it will select the elements you're interested in; then, it will hide those that match a simple filter based on value.