This turned out to be a pain, since you had to manually figure out what each width needed to be for the total size. To complicate things further, I wanted to have a different percentage width when accessing the colorpicker via an iPhone. I found that the hue slider was a little too small to accurately slide with the touch interface, so I wanted it to take up more of a percentage of the total width. I’m can be lazy about calculating widths in CSS, so I went off looking for a different way to do this.

Aspect Ratios

Why couldn’t I just use percentage widths? Because the left portion of the colorpicker needs to be a square – or else the gradients for saturation and value just look weird and don’t really map up 1:1. I did some searching and found a CSS workaround to keep the aspect ratio of a fluid element by ansciath. The meat of this trick is that according to the spec for margin-top, a percentage refers to the width of the containing block, not the height. This post got me much of the way there, but I had to include a couple of fixes for IE and ways.

The really nice part about using this technique is that it makes spectrum extremely easy to skin in your own CSS. Check out ColorStash for an example of this. Using media queries and max-widths, I can change the width of the colorpicker as the browser resizes to get some really responsive behavior on a UI control (colorpicker) that has typically been very static.

Demo

See the demo of the aspect ratio and media query. Try resizing your browser window to under 480px width to see the switch happen. Here is the full source code for the demo.

Below is a snippet showing the basic HTML/CSS needed for this technique:

<div class='container'>
    <div class='outer'>
        <div class='fill'></div>
        <div class='inner-top'>
            <div class='square'>Always a square</div>
            <div class='right'>% width</div>
        </div>
    </div>
    <div class='bottom'>
        Bottom
    </div>
</div>

.outer {
  position:relative; 
  width: 100%;
  display:inline-block;
}
.inner-top {
   position:absolute; top:0; left:0; bottom:0; right:0;
}
.square {    
    position: absolute;
    top:0;left:0;bottom:0;right:20%;
    background:orange; 
}
.right {
    position: absolute;
    top:0;right:0;bottom:0;left:83%;
    background: purple;
}
.fill { 
    *height: 80%;
    margin-top: 80%;  /* Same as square width */
}
@media (max-width: 480px) {
    .square { right: 51%; background: blue; }
    .right { left: 51%; }
    .fill { margin-top: 49%; } 
}

No Images!

It is pretty well known that you should limit the number of images that your web page requests for performance reasons. Some of these, including the eyecon.ro picker, which is the first that shows up when searching ‘jQuery colorpicker’, require a ton of images (27, in fact). This is overkill. Why can’t it be skinned with HTML/CSS?

Reasonable defaults

I found myself having to dig through the source code of various colorpickers in order to get them to act how I wanted. Maybe my experience on this is unique, but once I wanted to actually script behavior to go along with the picker (think – a template editor for an online portfolio), it became painful quickly.

Browser Support

It needs to support all major browsers (even IE). Ideally it could also support mobile devices.

Drop in

Didn’t want to have to download zip folders, place a bunch of images in my project and modify css files to point to the correct image path, etc. I just want to include a single JavaScript file, and a single CSS file, and be done.

Anything Like This?

I did find the nifty FlexiColorPicker, which accomplishes the no images goal with SVG and VML. It seems very nice, but didn’t have some of the features I wanted (dragging around the hue slider and picker didn’t actually work). I’m glad I found it, as I did use some of the gradients as a starting point with my CSS gradients.

Spectrum – My JavaScript Colorpicker

I have done a fair amount of color manipulation work while building a color scheme generator in a theme editor. I also have made a JavaScript color micro framework for parsing and conversion, called TinyColor. This is designed to allow a wide range of input and output (named colors, hex, rgb, hsl, hsv).

So, I decided to try my hand at this, and made the spectrum JavaScript colorpicker.

It works in all major browsers (tested in Safari, Chrome, Firefox, IE 7+, iOS, Opera). It uses IE’s propriety gradient filter (with some hacks for the hue slider – see .spectrum-ie-1 through 8 in spectrum.css. It should even work in iPhone and iPad – let me know if you have one and can double check that for me over on the demo page :). It is still in early stages, but I would love if I could get some feedback on the UI and desired functionality.

Demo

Head over to the current project page to try out the demo and see the docs.

It currently requires jQuery, but I have been trying to write the code to make it possible to remove that dependancy.

What is throttling?

Imagine you are scrolling down a long page for 3 seconds and you have bindWithDelay running with a timeout of 1000ms. By default, your event will only fire a second after you have completely finished scrolling. If you have the optional throttling on, it will fire once per second during the scrolling – a total of 3 times instead of 1.

Checkout the throttling demo to see what it is doing.

FileReader is a JavaScript interface that allows you to read local files as binary. This is available in supported browsers when a user drags and drops files into a browser window or selects files from an input with a type of file. See the FileReader specification for more information.

filereader.js is a wrapper for accessing this functionality. It can be called using:

FileReaderJS.setupInput(fileInput, opts);
FileReaderJS.setupDrop(dropbox, opts);

If you use jQuery, you can access these calls with:

$("#fileInput").fileReaderJS(opts);
$("#dropbox").fileReaderJS(opts);

To see the full range of options and functionality, view the readme.

filereader.js is available under the MIT License. See the full filereader.js code or the single file raw javascript source on github.

You can see an example project using filereader.js on Instant Sprite, a browser based CSS Sprite Generator that I am working on. Try dragging images onto the body, or clicking to add multiple image files to see what is possible.

For example, you want to use JavaScript to resize an iframe to 100% height when the window resizes. The resize() event can fire dozens of times, and calculating and setting the new height can slow down your page. I used to implement it like this (notice the extra global variable and indentation with the anonymous function):

var timeout;
function doResize(e) {
   clearTimeout(timeout);
   timeout = setTimeout(function() {
      // run some code
   }, 200);
}
$(function() {
   $(window).bind("resize",doResize);
});

I wrote a plugin to make this pattern easier, it is called “bindWithDelay”. The source code is online, as is a mini project page with a demo.

This is what the same code looks like with the plugin:

function doResize(e) {
      // run some code
}
$(function() {
   $(window).bindWithDelay("resize", doResize, 200);
});

This was fixed by adjusting the helper object for the sortable function. Check out the [article][] for all the details, but here is a sample of the code if you are just looking for the solution:

// Return a helper with preserved width of cells
var fixHelper = function(e, ui) {
	ui.children().each(function() {
		$(this).width($(this).width());
	});
	return ui;
};
 
$("#sort tbody").sortable({
	helper: fixHelper
}).disableSelection();

I wrote an article on the Foliotek Development Blog about saving the state of a variable inside a closure that is not executed immediately. For example, functions passed into event binding or setTimeout(). Here is a quick rundown of the problem and the solution (using the jQuery library).

The Problem

$(function() {
	$("body").append("<ul id='container'></ul>");
 
	for (var i = 0; i < 5; i++)
	{
		var $item = $("<li />").text("Item " + i);
		$("#container").append($item);
 
		$item.click(function() {
			alert("You clicked number " + i);  // always "You clicked number 5"
		});
	}
});

The Solution

$(function() {
	$("body").append("<ul id='container'></ul>");
 
	for (var i = 0; i < 5; i++)
	{
		var $item = $("<li />").text("Item " + i);
		$("#container").append($item);
 
		(function() { // Closure here here instead of "bindItem()"
			var ind = i;
			$item.click(function() {
				alert("You clicked number " + ind); // Works as expected
			});
		})(); // Execute immediately
	}
});

The solution uses an immediately executing function to create a new scope and declare a variable “ind” that is reserved a new space in memory instead of simply referencing “i”. Check out the full article for more details.

There came a time that I wanted to get the outerHTML of an element, and I found that Brandon Aaron shared a jQuery code snippet that does this exactly. It does the trick for most cases, but there was one problem that I ran into. I wanted to get the outerHTML of an element inside of an iframe, and I got a ‘Permission Denied’ error in Internet Explorer.

The problem was that it was appending an element belonging to the iframes ‘contentDocument’ into an element belonging to the global ‘document’ element.
Using the jQuery(html, ownerDocument) overload of the jQuery core function, this error was fixed:

$.fn.outerHTML = function() {
    var doc = this[0] ? this[0].ownerDocument : document;
    return $('<div>', doc).append(this.eq(0).clone()).html();
};

	<asp:TextBox runat="server" ID="txtPhoneNumber" />

renders out as something like:

	<input type="text" id="ctl00_ctl00_ctl00_main_Content_txtPhoneNumber" 
		name="ctl00$ctl00$ctl00$main$Content$txtPhoneNumber" />

I did a write up over on the LANIT development blog about a solution to this problem using jQuery.

Check out the post for more details, but here is the function:

	jQuery.expr[':'].asp = function(elem, i, match) {
		return (elem.id && elem.id.match(match[3] + "$"));
	};
 
	$(":asp(txtPhoneNumber)").keyup(...);