Sharepoint, AjaxControlToolkit, ModalPopup and DocType problems

I am currently integrating a Sharepoint web site with an ASP.Net web site. A Sharepoint web site is essentially an ASP.Net web site too, and Microsoft have provided a way to integrate exiting web sites into that, essentially by inheriting a Sharepoint master page.

My ASP.Net web site uses the AjaxControlToolkit. The problem is, the AjaxControlToolkit by default uses the XHTML DocType. Sharepoint doesn’t actually have a DocType specified, which means it defaults to HTML 4.0 transitional. That mode is ok. There are a number of reasons why you might want to use HTML 4.0 transitional. Most of the component libraries out there still use the old DocTypes because they offered a richer set of functionality. Recently I used the Intersoft control suite. These operates very strangely under  XHTML, and in fact they don’t support that mode.

But back to Sharepoint and the AjaxControlToolkit. I was trying to use the modal popup extender, so that I can have one of my forms displayed on clicking a button on the page. Without the DocType of XHTML, every time I clicked on the button, it would display the bottom-right hand corner of the dialog in the upper left-hand corner of my form, effectively clipping the control and making the control otherwise useless.

There are workarounds. You can go into the Modal Popup Extender and set the X and Y co-ordinates. The problem with that is that often you don’t know the exact co-ordinates where you want the popup to be displayed. Part of the desire to use the modal popup is because it centres on the page and will move with the page when you scroll. It also repositions itself when you adjust the form.

The answer to this is to obtain a re-write of the getClientBounds javascript function that goes into the AjaxControlToolkit source code, common.js file. This re-write may be obtained from here: and was put together by Umer Farooq of Islamabad.

Here it is repeated below:

getClientBounds : function() {
        /// <summary>
        /// Gets the width and height of the browser client window (excluding scrollbars)
        /// </summary>
        /// <returns type="Sys.UI.Bounds">
        /// Browser's client width and height
        /// </returns>

        var clientWidth;
        var clientHeight;
        switch(Sys.Browser.agent) {
            case Sys.Browser.InternetExplorer:
                if (document.documentElement && document.documentElement.clientWidth)
                    clientWidth = document.documentElement.clientWidth;
                else if (document.body)
                    clientWidth = document.body.clientWidth;
                //clientWidth = document.documentElement.clientWidth;
                if (document.documentElement && document.documentElement.clientHeight)
                    clientHeight = document.documentElement.clientHeight;
                else if (document.body)
                    clientHeight = document.body.clientHeight;
                //clientHeight = document.documentElement.clientHeight;               
            case Sys.Browser.Safari:
                clientWidth = window.innerWidth;
                clientHeight = window.innerHeight;
            case Sys.Browser.Opera:
                clientWidth = Math.min(window.innerWidth, document.body.clientWidth);
                clientHeight = Math.min(window.innerHeight, document.body.clientHeight);
            default:  // Sys.Browser.Firefox, etc.
                clientWidth = Math.min(window.innerWidth, document.documentElement.clientWidth);
                clientHeight = Math.min(window.innerHeight, document.documentElement.clientHeight);
        return new Sys.UI.Bounds(0, 0, clientWidth, clientHeight);

Basically, it works by detecting various instances of objects on the client in the Internet Explorer part of th code. If XHTML is present, document.documentElement.clientWidth exists, otherwise it will use the default document.body.clientWidth.

There is a second issue, that is to do with the positioning of the modal background. Basically, because the modal popup defaults to position:fixed, the background positions itself within the content part of the page. This is not desirable, as we want it to make the entire page inoperable while our dialog is showing. I actually don’t like the use of position:fixed, because it is unavailable in IE6. To solve this problem, simply find references to ‘fixed’ in the ModalPopupBehavior.js file in the AjaxControlToolkit and change them to ‘absolute’. You might want to alter the left and top values for the background element in this file too. I changed mine from zero (0) to minus 1 (-1).

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