During testing what we found that our some pages throwing below mentioned error in Chrome browser.
Cannot read property '_notified' of null
The problem is that the browser detection code in MicrosoftAjax.js does not detect WebKit (gasp!). Include this javascript code to your page in which you are getting error.
Sys.Browser.WebKit = {};
if (navigator.userAgent.indexOf('WebKit/') > -1) {
Sys.Browser.agent = Sys.Browser.WebKit;
Sys.Browser.version = parseFloat(navigator.userAgent.match(/WebKit\/(\d+(\.\d+)?)/)[1]);
Sys.Browser.name = 'WebKit';
}