If you’re testing your ASP.NET project in Internet Explorer 10, you may encounter following error:

SCRIPT5022: Sys.ArgumentOutOfRangeException: Value must be an integer.
Parameter name: (x or y)
Actual value was (some floating point value)
ScriptResource.axd, line … character …

Often it come up when you use some 3rd party libraries, Telerik or Infragistics (in my case it happened in WebDataMenu control).

Here why it happens. Actual error happens in Sys.UI.Point class. In its constructor it expects 2 parameters – x and y. If you trace the callstack you will see that these values are provided to the class by a preceding call to browser’s intrinsic function getBoundingClientRect(). In previous versions of IE it returned Integer values. But in IE10 values are floating point.

Now if you’re using older version of .NET Framework (e.g. 3.5 or below) you’ve got a problem. Sys.UI.Point class expects parameters to be strictly Integer. Since IE10 provides fractionals – error shown above is thrown.

There could be other incompatibilities, so the only real, non-hacky solution, well – upgrade your project to a more recent version of .NET framework (4.5 at the time of this post).

If upgrading is not possible and you’re willing to accept the risk of a hack – include following function into your page:

Sys.UI.Point = function Sys$UI$Point(x, y) {

    x = Math.round(x);
    y = Math.round(y);

    var e = Function._validateParams(arguments, [
        {name: "x", type: Number, integer: true},
        {name: "y", type: Number, integer: true}
    ]);
    if (e) throw e;
    this.x = x;
    this.y = y;
}

This function will replace original one and the only addition is rounding of incoming parameters.

---

UPDATE 6/6/2013: After playing with this for a while I realized one interesting thing – the above error happens only if my project is in debug mode <compilation debug="true"> is set. As soon as I change it to <compilation debug="false"> the error goes away. You may still have to update browser definition file to avoid ‘_doPostBack’ is undefined JavaScript error, but that’s another story.