Drupal 6 JavaScript and jQuery - Ebook-Cours.com

Working with JavaScript in Drupal
Let's consider an example. The main function in our printer_tool.js file is named
print(). But print is a very common name, and the built-in JavaScript window
object already has a function named print(). So how do we distinguish
our print() from window's print()?
One popular method of solving this problem is to assign objects to namespaces.
Then the developer can explicitly specify which print() ought to be used.
Let's look at the next line of the script for an example:
PrinterTool.windowSettings = 'toolbar=no,location=no,' +
'status=no,menu=no,scrollbars=yes,width=650,height=400';
Here we create the windowSettings string object, assigning it a long value that will
later be used when calling JavaScript's built-in window.open() function.
But windowSettings is defined as a member of the PrinterTool namespace.
If we were to insert the following code directly beneath the previous line, what
would happen?
alert(windowSettings);
We would get an error since there is no object in the current context named
windowSettings. To retrieve the value of the windowSettings object, we would
need to write this instead:
alert(PrinterTool.windowSettings);
Now the alert dialog would be created and populated with the string 'toolbar=no,
location=no,status=no...'.
That is how namespaces function. If we were to call print(), it would use the
window.print() function. Remember, window is the default scope for browser-based
JavaScript. To call the print() function, which this script defines, we would have to
provide the full namespace PrinterTool.print().
Since we are talking about it already, let's take a closer look at the PrinterTool.
print() function.
The print() function
The PrinterTool.print() function looks like this:
/**
* Open a printer-friendly page and prompt for printing.
* @param tagID
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This material is copyright and is licensed for the sole use by Richard Ostheimer on 18th June 2009
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