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Advanced Web Design | ||
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Scripting Database |
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The Status Scroller Function |
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| A scroller is text which scrolls on
the status bar of the browser. Take a look at your status bar to see my
scroller. Scrollers are very popular with JavaScript authors (esp. newbies
like ourselves) and equally unpopular with the rest of the Web community.
Programming the ScrollerHow much programming does it take to create a scroller? Twenty lines, to be exact, as you will see. But before we go into the code, let us understand what features of JavaScript makes the scroller possible. First is the ability to write to the status bar using the window.status
property like this: The second is the setTimeout() function. This function takes two parameters. The first is a string specifying the JavaScript statement to be executed on triggering and the second is a number specifing time in milliseconds after which triggering occurs. Our scroller is essentially a function which, on each invocation, moves the text on the scroll bar a little to the left and then calls setTimeout() to invoke itself after a small interval of time. Here is the complete code for the scroller. The only other function we use is substring() which is a method
of the string object. If
Getting the Scroller on your pageIf programming is not one of your strong points, you can still have the scroller on your page. Just copy the above code into your HTML file, preferably between <HEAD> and </HEAD> tags and change the scrollText and scrollDelay variables in lines 4 & 5 to suit yourself.
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