Programming with JavaScript - HTML, CSS, and Dynamic HTML - page 712

Figure 10-17 calling a javascript function

function call

HTML code written to the Web page

function code

Parameter values can also themselves be variables. The following commands store
the library name in a text string variable named libText and call the showMsg() function
using that variable as the parameter value:

varƒlibText=”CutlerƒPublicƒLibrary”;
showMsg(libText);
As a result, the following HTML code would be written to the Web document:

<p>WelcomeƒtoƒtheƒCutlerƒPublicƒLibrary</p>
Functions can be called repeatedly with different parameter values to achieve different
results. For example, the following code calls the showMsg() function twice with differ-
ent parameter values to display two welcome paragraphs—one for the Monroe Public
Library and one for the Cutler Public Library:

varƒlibTextƒ=ƒ“MonroeƒPublicƒLibrary”;
showMsg(libText);
varƒlibText2ƒ=ƒ“CutlerƒPublicƒLibrary”;
showMsg(libText2);
You can call the showEM() function that you just entered to display the hypertext link
for Catherine Adler's e-mail address. The command is

showEM(“cadler”,”mpl.gov”);
As a result of this command, the userName parameter would contain a text string of
cadler and the emServer parameter would contain the text string mpl.gov . You're ready
to replace the commands you entered earlier to write the hypertext link for Catherine
Adler's e-mail address by calling the showEM() function.

To call the showEM() function:

◗

1. Return to the mpl.htm file in your text editor and then scroll down the file to the
script element containing the JavaScript code for Catherine Adler's e-mail address.

◗

2. Replace all of the commands within the script element with the following com-
mand, as shown in Figure 10-18:

showEM(“cadler”,”mpl.gov”);