Joseph Michael Pesch
VP Programming

Sys Undefined Exception in ASP.Net Web Form Menu Control Generated JS with URL Routing

by 16. October 2012 08:07

Although the exception only seems to occur when using URL routing it is not consistent (i.e. doesn't always happen).

The page generates this line at the end of the Form tag:

new Sys.WebForms.Menu({ element: 'Navigation Menu', disappearAfter: 500, orientation: 'horizontal', tabIndex: 0, disabled: false });

Throws JS runtime exception:

'Sys' is undefined


void Application_Start(object sender, EventArgs e)


  <pages controlRenderingCompatibilityVersion="3.5"/>


ASP.Net | C# | JavaScript

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