There are several ways to embed JavaScript into your HTML
pages . Lets look at them
the <SCRIPT> tag .
JavaScript code appears between a <SCRIPT>
and a </SCRIPT> tags . You can use just the
basic <SCRIPT> tags for your scripts like
the following
<SCRIPT>
document.write("A JavaScript example ");
</SCRIPT>
which gives us the following output
there are a number of attributes which we can use with
the <SCRIPT> tag
LANGUAGE
This is used to specify what scripting language the script
is written in . In the majority of browsers the default
attribute is JavaScript . But you have to be aware that
there is also VBScript as well . If you were to mix VBScript
and JavaScript and didn't specify the language you would
get some interesting problems cropping up . You can set
the LANGUAGE attribute to the actual version number of JavaScript
so if you set it to JavaScript 1.1 you would get all of
the features of JavaScript 1.1 but if your script had features
that were introduced in a later version of JavaScript the
script would fail .
SRC
this is used to specify the URL of an external script to
be loaded and executed . These external files usually have
a .js extension . So this would look like this <SCRIPT
SRC = "sample.js"></script>
ARCHIVE
this is used to specify the URL of a JAR file that contains
a script specified by the SRC attribute . JavaScript 1.2
required.
TYPE
This is only supported in Internet Explorer 4 and Netscape
Navigator 4 upwards . The syntax is as follows
<SCRIPT TYPE = "text/JavaScript">my javascript
</SCRIPT>
Event Handlers
JavaScript code can also be put into the handler attributes
of HTML tags . These attributes always begin with on and
some examples are onClick , onBlur and onMouseDown . The
code is executed when the event occurs so for example if
you press a button and have JavaScript code attached to
the button this will execute when the button is pressed
. Here is an example .
Here is the HTML for this example
<INPUT TYPE = button VALUE = "Press me for an alert box"
onClick="alert('damn annoying alert box example');">
JavaScript URLs
A JavaScript URL is a special type of URL . A JavaScript
URL does not send or retrieve any information like a normal
URL except as a side effect A JavaSCript URL is used
to execute a script . JavaScript URLs occupy a single line
, so if the contain more than one statements , semi-colons
should be used .
