ObjectSwap does not work with YouTube videos

Youtube provides a object tag that you can include on your site to show the videos directly, w/o making the user leave your site.

However, I noticed that this object tag was not being activated with the objectswap technique which makes it so you don’t have to click on the flash object to “activate” it in IE.

To fix this you need to include the type=”application/x-shockwave-flash” in the object definition.

I am not sure why you need this, but if you leave it out, somehow IE removes the object from it’s DOM.

If you allow a page to load w/o this “type” and then try to find, using javascript, any OBJECT tags and it will tell you there are none.

 

UPDATE:  Still having some problems… thinking the trick above is causing some new problems.

Dynamically Resizing an IFrame to Fill The Browser

If you ever work with an IFrame, you will notice that you can’t set height=100%.

But, many times you might want to have an IFrame act as if that property had the desired effect.  i.e. If you make your browser window taller, you want the heigh of your IFrame to grow as well.

You can acheive this using the following script:

       function resize_iframe() {
            var myWidth = 0, myHeight = 0;
            if( typeof( window.innerWidth ) == 'number' ) {
                //Non-IE
                myWidth = window.innerWidth;
                myHeight = window.innerHeight;
            } else if( document.documentElement && ( document.documentElement.clientWidth || document.documentElement.clientHeight ) ) {
                //IE 6+ in 'standards compliant mode'
                myWidth = document.documentElement.clientWidth;
                myHeight = document.documentElement.clientHeight;
            } else if( document.body && ( document.body.clientWidth || document.body.clientHeight ) ) {
                //IE 4 compatible
                myWidth = document.body.clientWidth;
                myHeight = document.body.clientHeight;
            }

            var iNewHeight;
            iNewHeight = parseInt(myHeight)-40;
            document.getElementById("WgipIFrame").style.height = iNewHeight;
        }

        //-- see if there is already something on the onresize
        var tempOnresize = window.onresize;
        //-- create our event handler
        window.onresize = function(){
            //-- if tempFunc is a function, try to call it
            if (typeof (tempOnresize) == "function"){
                try{
                    tempOnresize();
                } catch(e){} //--- if it errors, don't let it crash our script
            }
            resize_iframe();
        }

Then you can set the IFrame’s onload=”resize_iframe();” like this:

<iframe src="x.htm" style="width:100%;"
  id="WgipIFrame" name="WgipIFrame"
  onload="resize_iframe();"></iframe>

 

Finding Browser Window Height

Here is a nice script, part of a larger section on getting window size/positions and scroll data out of various browsers.  This page really has a lot of good information.

function alertSize() {
    var myWidth = 0, myHeight = 0;
    if( typeof( window.innerWidth ) == 'number' ) {
        //Non-IE
        myWidth = window.innerWidth;
        myHeight = window.innerHeight;
    } else if( document.documentElement && ( document.documentElement.clientWidth || document.documentElement.clientHeight ) ) {
        //IE 6+ in 'standards compliant mode'
        myWidth = document.documentElement.clientWidth;
        myHeight = document.documentElement.clientHeight;
    } else if( document.body && ( document.body.clientWidth || document.body.clientHeight ) ) {
        //IE 4 compatible
        myWidth = document.body.clientWidth;
        myHeight = document.body.clientHeight;
    }
    window.alert( 'Width = ' + myWidth );
    window.alert( 'Height = ' + myHeight );
}

Using window.onload without overwriting existing onload event handlers

When you are creating reusable javascript files, there are times when you want to tap into the window.onload event, which is fired when the window has finished loading the content.

The problem here, is that you can’t have multiple event handlers for the same event.

So if you have a page that uses 2 scripts which both use the window.onload event, then which ever is loaded last will win, and the other script will never catch the event.

Well one way you can deal with this problem is to write your window.onload (or other events for that matter) using this type of a pattern:

    //-- see if there is already something on the onload
    var tempFunc = window.onload;
    //-- create our event handler
    window.onload = function(){
        //-- if tempFunc is a function, try to call it
        if (typeof (tempFunc) == "function"){
            try{
                tempFunc();
            } catch(e){} //--- if it errors, don't let it crash our script
        }
     //-- Call your onload function here
    }

This way, you can have several function that all utilize the onload event, and none of them have to know about each other.

 

Adding return values to SubModal

A while back I blogged about SubModal, a little tool for creating nice modal dialogs on websites.

One of the things I wanted to do was have the modal dialog return a value, like the showModalDialog does in IE.

To achieve this, follow these instructions.

In your “main” html page, declare a callback function and a button that will launch the modal dialog:

    function myFunction(val){
        alert("Return value is...");
        alert(val);
    }

Then create an input button to launch the modal dialog.

<input type="button" onclick="showPopWin('modalcontent.html', 400, 200, myFunction);" />

Then, in the submodalsource file, or where ever you have your JS stored, change this function to include a return value, and have it use it.

/**
 * @argument callReturnFunc - bool - determines if we call the return function specified
 * @argument returnVal - anything - return value
 */
function hidePopWin(callReturnFunc, returnVal) {
    //alert(callReturnFunc);
    gPopupIsShown = false;
    restoreTabIndexes();
    if (gPopupMask == null) {
        return;
    }
    gPopupMask.style.display = "none";
    gPopupContainer.style.display = "none";
    if (callReturnFunc == true && gReturnFunc != null) {
        // edited by CDM -- gReturnFunc(window.frames["popupFrame"].returnVal);
        gReturnFunc( returnVal );
    }
    gPopFrame.src = gLoading;
    // display all select boxes
    if (gHideSelects == true) {
        displaySelectBoxes();
    }
}

Then finally on your modal page, just some code to close the window, and pass back the return value.

<button onclick="window.parent.hidePopWin(true, 'I am the return value')">close</button>

The top 10 mistakes when using AJAX

Here is an interesting list of the top 10 things people do wrong when using AJAX.

http://weblogs.asp.net/mschwarz/archive/2006/11/20/the-top-10-mistakes-when-using-ajax.aspx

  1. Don’t use AJAX to update the complete page by putting everything in a UpdatePanel. You want to save time and traffic when running the web page. Never update parts of the web site that can be changed using JavaScript and DHTML (DOM).
  2. Have in mind that there are a couple of visitors that have JavaScript disabled or using a web browser with an older or less JavaScript implementation like the most mobile devices have. What does your visitor see if everything is disabled? I don’t recommend to have the full web site available as a JavaScript disabled version!
  3. Cache the same requests on client-side web browser or implement any caching on the web server. The most used scenarios like AutoComplete or DropDown fields are filled everytime the same. A wrong written AutoComplete can slow down your web server (database server) because there more requests done than the version before using PostBacks. Think of pressing F5 (reload) all the time with your old web site. If you have cascading DropDown you can save more traffic/requests!
  4. Don’t run concurrent or long running AJAX requests when using CSS or JavaScript to change the UI. There are only two concurrent http connections possible with all common web browsers (I know you can change this, but the default behavior is set to two). If there are running to many AJAX requests running loading of images will be slow down.
  5. Use everytime the asynchrouns invoke of the send method of XMLHttpRequest. There is no issue where you want to use the synchronous one. Your web browser will not be forozen when having network problems or slow connections.
  6. Try your web application using a very slow internet connection. Try it again using a TCP/IP connection with a very high latency for each paket.
  7. Is your web application running as a desktop replacement? Have a look at the memory usage of common web browsers if you run your application one hour, two hours or couple of days. Not everybody has a development machine like yours!
  8. Check the http status code you will get back from XMLHttpRequest. There are a couple of common network errors like DNS not available, http server error 500. Did you ever checked for the status code which tells you if your web browser is in offline mode?
  9. Try to disable the XMLHttpRequest object! With IE7 you can use the native object instead of the ActiveX object, but you can still disable the native object, too.
  10. Check your AJAX requests for security issues! Did you simple open all your data access layers? Make use of FormsAuthentication and PrincipalPermissions on ASP.NET. Can anybody create requests (not only by clicking on a link)?

Client Side Modal Dialogs (SubModal)

One thing that I really like about IE, but is not available in other browsers is the client side modal dialog.

A modal dialog is a popup window that must be acted on (or closed) before you can do anything else on the window underneath.

I came across a nice modal dialog being used on the forums.asp.net site.  I ended up emailing the guy who wrote the editor I was using, and he directed me to the original creator of the dialog “submodal.”

Some people have made updates and extensions to submodal, and there has been a google group created for the discussion of submodal.

It is still not clear to me if this technique will allow you to pass back a value from the modal dialog to the opening page, because I think that is a very important feature, but I don’t see any direct reference to it.

AJAX Toolkit Library Growing

A while back I was looking at the AJAX toolkit page (http://ajax.asp.net/ajaxtookit) and I was really not impressed with anything I saw.

Things like the “Confirm” button, which is basically a button with 10 seconds of javascript coding built into it isn’t a big deal, IMO.

But their list of controls has really grown and there are some really interesting things in that toolkit.

It still boggles my mind that they don’t have an autocomplete dropdown list where your selections are LIMITED to the choices from the list.