Peter Velichkov's Blog

A common case for most ASP.NET sites is slow frontend rendering due to many Javascripts. The typical requests graph looks like this:

All these AXD files are embedded Web Resources usually Javascripts and sometimes CSSs. The bad news about having many embedded Javascripts are:

1. Many HTTP Requests (meaning generating more load to the web server)
2. Poor rendering time because when the browser starts downloading a Javascript file it stops downloading(rendering) everything else (easily seen on the graph)
3. Less chance for caching any of those files
4. If HTTP compression is enabled in the IIS many files mean more load and worse compression ratio than one merged file.

The most common scenario for having many embedded Javascripts is either using AJAX or some commercial .NET controls.

The solution for merging AJAX AXDs in a single file is described in those two great posts:

Script combining made easy [Overview of the AJAX Control Toolkit's ToolkitScriptManager]

and

Script combining made better [Overview of improvements to the AJAX Control Toolkit's ToolkitScriptManager]

The recapitulation when with a friend of mine (Julian) tested out this technique was reducing the loading time with about 2 seconds on a quite clean and well build site. Also the better HTTP compression reduced the size a bit.

If you are using ComponentArt’s Web.UI version 2007.2 or later controls there is solution posted on their blogs too:

Optimizing Web.UI Client Script Deployment

And couple more general advices:

1. If it depends on you merge all your Javascript and CSS files
2. Load CSS at most top of you page
3. Load Javascripts at most bottom of your page (if possible)
4. Minify both Javascripts and CSSs
5. Be smart

Update: Stefan Dobrev sent me a link for moving the AJAX Javascripts to the bottom (point 3 of the list above) which should improve rendering time too. Thanks Stefan

Just refactored the input watermarking script, of course it is still XHTML 1.0 transitional and WCAG priority 1,2 valid.

JavaScript:

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24

 
// This Javascript is written by Peter Velichkov (http://www.creonfx.com)
// and is distributed under the following license : http://creativecommons.org/licenses/by-sa/3.0/
// Use and modify all you want just keep this comment. Thanks
 
var values = new Array();
var inputs = new Array();
 
function addWaterMark(el){
	try {
		values.push(el.value);
		el.addEvent('focus',function(){
			if (el.value === values[inputs.indexOf(el)]){el.value = ''};
		});
		el.addEvent('blur',function(){
			if(this.value === ''){el.value = values[inputs.indexOf(el)]};
		});
	} catch(e) {dbug.log('addWaterMark: ', e)}
};
window.addEvent('domready', function(){
	inputs = $$('input.watermark');
	inputs.each(addWaterMark);
});
//-->

Usage: Just put value on you inputs and use class=”watermark”

As usual example

Thanks to Aaron Newton from CNET.com for refactoring my PNG Fix script and increasing its quality and speed.

As usual for dessert explanations + demo and source code

Got tired of not able to style (colors, padding, background image, etc) dropdowns under various browsers (Internet Explorer and Safari are proven worst). Using my very favorite javascript framework mootools I created some simple dropdown simulating the select and option html tags usage.

Picture == thousand words

and example of custom styled dropdown

I have previously read about Javascript ways to make rounded corners but non of the suggested techniques produced antialiased (smooth) corners making me skeptic about the whole concept but curvyCorners proved me wrong - nice rounded corners with arbitrary radius, options for anti-aliasing and borders - Great work Cameron! I also tried the YUI compressor and was able to reduce the size significantly compared to the light version provided. If there is interest I can upload the compressed version.

As usual a demo is worth thousand words

As always when I need to use some transparent images cursing Internet Explorer 6 is inevitable so i wrote a quick javascript fix. Again mootools was the preferred framework because the ease of use.

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59

// This Javascript is written by Peter Velichkov (www.creonfx.com)
// and is distributed under the following license : http://creativecommons.org/licenses/by-sa/3.0/
// Use and modify all you want just keep this comment. Thanksfunction fixPNG(){
 
 $$('*').each(function(el){
 
 	var imgURL = el.getStyle('background-image');
 
 	var imgURLLength = imgURL.length;
 
 	if ( imgURL != 'none' && imgURL.substring(imgURLLength  - 5, imgURLLength  - 2) == 'png'){
 
 		el.setStyles({
 
 			background: '',
 
 			filter: "progid:DXImageTransform.Microsoft.AlphaImageLoader(enabled='true', sizingMethod='crop', src='" + imgURL.substring(5,imgURLLength  - 2) + "')"
 
 		});
 
 	};
 
if(el.getTag() == 'img' && el.getProperty('src').substring(el.getProperty('src').length  - 3) == 'png'){
 
 		var imgReplacer = new Element('input', {
 
 			'styles': {
 
 				'filter': "progid:DXImageTransform.Microsoft.AlphaImageLoader(enabled='true', sizingMethod='crop', src='" + el.getProperty('src') + "')",
 
 				'position': 'relative',
 
 				'background': 'transparent'
 
 			},
 
 			'title': el.getProperty('alt')
 
 		});
 
imgReplacer.setStyles(el.getStyles('padding','margin','border','height','width'));
 
 		imgReplacer.setProperties(el.getProperties('id','class'));
 
 		imgReplacer.disabled = true;
 
 		el.replaceWith(imgReplacer);
 
 	};
 
 });
 
}
 
if(window.ie6){
 
 window.addEvent('domready', fixPNG);
 
}

Fix description: First I’m looking for all tags that have background-image style and replace it with Microsoft AlphaImageLoader filter, then I search for all <img> tags and replace them with <input> (img src used for style background image again using the MS filter). I used input since it is inline element but still has height and width - like the img tag.

PS. If you use any links in area with PNG used for bg put the links in div with style=”position:relative” else they will not be clickable due to the MS filters

and as always example: IE6 PNG Transparency Fix with JavaScript

Something that really stops tableless layouts is the lack of ability to make two or three columns the same height. There are a lot of tricks but the solution I prefer is with Javascript.

Description of the solution: I used the mootools framework since it provides lots of useful predefined methods, selectors etc.

Usage: Just include the latest mootools js file (don’t need ajax, json, fx and other) and the following js. Than add the class defined in the function (class=”equals” in the example) to the columns you want to be in equal height.

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30

// This Javascript is written by Peter Velichkov (www.creonfx.com)// and is distributed under the following license : http://creativecommons.org/licenses/by-sa/3.0/
// Use and modify all you want just keep this comment. Thanks
 
function equalHeight(cl){
	var className = '.' + cl;
	var maxHeight = 0;
	$$(className).each(function(el) {
	if (el.offsetHeight & gt; maxHeight) {
		maxHeight = el.offsetHeight;
	}
	});
 
	if ($$('.dummyExtender') != '') {
	$$('.dummyExtender').each(function(el) {
		el.setStyle('height', maxHeight - el.getParent().offsetHeight + el.offsetHeight);
	});
	} else {
	$$(className).each(function(el) {
		var curExtender = new Element('div', {
		'class': 'dummyExtender'
		});
		curExtender.injectInside(el);
		curExtender.setStyle('height', maxHeight - el.offsetHeight);
	});
	}
}
 
window.addEvent('load',function() {
    equalHeight('equals');
});

Example: Equal Height DIV Columns

Update: Also since Internet Explorer 6 adds silly spacing in DIVs add the following lines to your css:

.dummyExtender{
font-size:0;
line-height:0;
padding:0;
margin:0;
}