Microsoft JScript runtime error: 'document.getElementById(...)' is null or not an object

Hi,

This is typical javascript problem, when you use. Because the front end gives the compilation error when the control no more there in design page. But the javascript doesn't. but gives the critical issue at the run time.

Some times the user write some javascript for the controls and finally they will remove that control. Still javascript code will be there then it throws error.

Always, recommended to check object before use them.

if(document.getElementById('txtusername'))
{
         document.getElementById('txtusername').value = 'test';
}

Here if that control exists then only returns true and assign the value. Even if you remove the control will not give any error.

Hope this will help you to fix.