WebMastersLoom

When designing elements for your webpage, you will often be called upon to specify a color. For example, the code for a span shown below specifies that the color of the text within the span will be yellow.

<span style=”color:yellow;”>Text</span>

Colors can be specified according to their names, for example “yellow”, “green”, or “blue”. In many cases, these simple color names will work. But what if you want to specify a more sophisticated color like “cornflowerblue”? A particular browser may not recognize a particular color name. It’s more reliable to specify colors with an “RGB triplet”.

An RGB triplet specifies a color based upon the amounts of red, green, and blue, on a scale from 0 to 255, required to create the color. For example, to create the color cornflowerblue you need red=100, green=149, and blue=237. We could then specify the color of the text within a span using the rgb function as shown below.

<span style=”color:rgb(100,149,237);”>Text</span>

This will work fine with style notation, but what if you want to use straight html. Html doesn’t recognize the rgb function. In that case, you can specify color using “hexadecimal” notation. Whereas the decimal numbering system uses the characters 0 through 9 to get 10 values, the hexadecimal numbering system uses the characters 0 through f to get 16 values. (After 9 the characters a, b, c, d, e and f are used, as shown below.)

Decimal Hexidecimal Equivilants

dec hex
0 = 0
1 = 1
2 = 2
3 = 3
4 = 4
5 = 5
6 = 6
7 = 7
8 = 8
9 = 9
10 = A
11 = B
12 = C
13 = D
14 = E
15 = F

On first appearance, this looks pretty simple but you need two hexadecimal characters to represent all decimal values from 0 to 255. When you increment decimal 9 by 1, you change the 9 to 0 and put 1 in the ten’s place. When you increment hexidecimal F by one, you change the F to 0 and put 1 in the “sixteens” place. Sometimes it’s not easy to convert between decimal and hexadecimal in your head.

RGB Triplet for Cornflowerblue

color   dec   hex
red     100    64
green   149    95
blue    237    ED

We could then specify the color of text within a span using the hexadecimal notation as shown below.

<span style=”color:#6495ed;”>Text</span>

Note that when we indicate the use of hexadecimal notation by placing a pound (#) sign in front of the number, and we don’t use commas to separate the color components.

If it’s not easy to convert between decimal and hexadecimal in your head, then how do you do it? You can use a calculator that has a decimal to hexadecimal coversion function, or you can learn to think in hexadecimal. For example, what’s the next number after CE? That would be CF. what’s the next number after CF? That would be D0. Which hexadecimal number is higher 99 or B2? B2 would be higher than 99. It gets easier with experience.

Here’s Java Script code for a simple decimal to hexidecimal color converter

function convert(decvalue)
{
var num = parseInt(decvalue);
if(num >= 0 && num < 256)
{
var hexnum = num.toString(16);
alert("#" + hexnum);
}
else {alert("Error!");}
}

It’s important to use hexadecimal notation to specify colors when you use DHTML with visual effects, because to create a dynamic color change you have to increment or add a value to a color. The vast amount of color specification on webpages is in hexadecimal notation, so it would be wise to become familiar with it.

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You can make it easier for your visitors to subscribe to your RSS feed. With a free and easy to install javascript function you can add the QuickSub feed button to your webpage in just a few minutes. Let me show you just how easy it is.

QuickSub is a javascript mouseover function that produces a list of RSS feed readers that you can use to subscribe to your RSS news feed with one click. You can see it in action on my RSS resource site, just move the mouse over the subscribe link. You should see a list of RSS feed readers. If you click on one of the news reader links it will open up that RSS reader and add this feed to it. You will need the particular news reader installed on your computer for this to work. So for example if your visitor uses SharpReader as their RSS reader then they would click on the Sharpreader link and this would add your feed to your visitors RSS reader.

To use QuickSub on your site you will first need to download the javascript and CSS files from QuickSubs site. The file is compressed so you will need to unzip the file which will leave you with quicksub.css and quicksub.js as well as a sample html file.

Upload the CSS as javascript file to your server. Now you will need to add some code into your web pages. You will need to do this for all of the pages that you wish to use QuickSub on.

Please note that in these examples I have used square brackets instead of angled brackets.

First you need to copy some code to call the CSS file. Add this line with your head tags.

Then copy this code into the body of your page.

<div id="quickSub" style="position:absolute; visibility:hidden; z-index:1000;" onMouseOut="return timeqs();" onMouseMove="return delayqs();"></div>

Then where you want to use QuickSub place this code in the body of your page.

 <a href="http://www.sitename.com/rssfeed.xml" onmouseout="return timeqs();" onmouseover="return quicksub(this, 'http://www.sitename.com/rssfeed.xml');">Your link text here</a>

You just need to replace the path with the path to you RSS feed and enter you own link text. All is left now is to upload your modified page to your web server and the new QuickSub javascript will be active.

Its generally a good idea to let users of your site bookmark your page. While most browsers support this function through “Favourites”, why not make it easier for you site visitors. You more likely to get repeat visitor if your site is bookmarked.

Here is a simple JavaScript function you can use to create a bookmark.

function addbookmark() {
  bookmarkurl="http://www.mysite.com"
  bookmarktitle="BookMark Title of My Site"
  if (document.all)
    window.external.AddFavorite(bookmarkurl,bookmarktitle)
}

Now create a text link which refers to the bookmark function as follows.

<a href="javascript:addbookmark()">Bookmark this Page</a>

Thats it. Feel free to replace the text with a graphic if you prefer.

PS. If you like this code sample, please link to our site (http://www.webmastersloom.com). It will be much appreciated.