Thursday, 1 May 2014

.NET - How to fix error Message 'Sys.WebForms.PageRequestManager' is null or not an object

Error message: Message 'Sys.WebForms.PageRequestManager' is null
 not an object or 0x800a138f - JavaScript runtime error: Unable to get property 'PageRequestManager' of undefined or null reference

watch on YouTube:
while trying to execute the following code: Sys.WebForms.PageRequestManager.getInstance().add_beginRequest(doSomething);

To fix it:

 In web.config replace  
    <xhtmlConformance mode="Legacy" />

    <xhtmlConformance mode="Transitional" />

1 comment:

  1. Thank you so much!!
    It worked finally.