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Hello World #3: Using a Function to Say Hello
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<SCRIPT LANGUAGE="JavaScript"><!-- hide from old browsers
/*
THE JAVASCRIPT COOKBOOK by Erica Sadun, webrx@mindspring.com
Copyright (c)1998 by Charles River Media. All Rights Reserved.
This applet can only be re-used or modifed by license holders of the
JavaScript Cookbook CD-ROM. Credit must be given in the source
code and this copyright notice must be maintained. If you do
not hold a license to the JavaScript Cookbook, you may NOT
duplicate or modify this code for your own use.
Use at your own risk. No warranty is given or implied of the suitability
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*/
function userAlert()
{
alert("Hello World!");
}
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<FONT COLOR="007777"><H1><IMG SRC="../GRAFX/UTENS.JPG" WIDTH=80 HEIGHT=50
ALIGN = LEFT>Communications 103</H1></FONT>
<BLOCKQUOTE>
<FONT COLOR="770000">
I will say "Hello World" to the reader with an Alert box when
he presses the button below.
</FONT>
<FORM>
<INPUT
TYPE="button"
VALUE=" Say Hello World to the Reader "
onClick="userAlert()"
>
</FORM>
</BLOCKQUOTE>
<FONT COLOR="007777"><H2>Discussion</H2></FONT>
<FONT SIZE=4>
This third "hello" program uses an alert box
to greet the reader.
There are no JavaScript calls from the HTML body.
Instead, a Button's
<FONT COLOR="770000">onClick</FONT> event
is used to trigger the call to our
<FONT COLOR="770000">userAlert</FONT> function.
In JavaScript, users create <b>events</b> by
moving the mouse over links, clicking buttons,
activating or deactivating text fields
and so forth. Events provide a standard
way to trigger JavaScript functionality.
<h3>The userAlert() function</h3>
<font color="770000" size=3><pre><null
>function userAlert(){<br><null
> alert("Hello World!")<br><null
>}<br>
</pre></font>
<h3>The Event Call</h3>
<font color="770000" size=3><pre><null
><FORM><br><null
> <INPUT <br><null
> TYPE="button"<br><null
> VALUE=" Say Hello World to the Reader "<br><null
> onClick="userAlert()"<br><null
> ><br><null
></FORM>
</pre></font>
</FONT>
<h5>Copyright ©1996 by Charles River Media, All Rights Reserved</h5>
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