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Introduction to Web Programming
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There is one more very handy trick that can be performed through
HTML. Suppose we wanted to use our Hello applet in a little more
generic manner. Instead of simply displaying "Hello Cyberspace",
suppose we wanted it to be able to display any phrase determined by
the person who codes the HTML.
- To do so, we need only make a simple
modification to the Hello applet to change it to display some text
we define in the HTML instead of having a hard-coded string defined
in the code.
- Specifically, you can pass parameters to
an applet by specifying them in the applet's HTML between the start
applet tag and the end applet tag. For example the following HTML
passes two parameters to the Hello applet:
<APPLET WIDTH = "200" HEIGHT = "100"
CODE = "Hello.class">
<PARAM NAME = "text" VALUE = "Have a nice day">
<PARAM NAME = "speed" VALUE = "low">
</APPLET>
- The first parameter is named "text" and has
a value of "Have a nice day". The second parameter is named "speed"
and has a value of "low".
- In your applet, you can access these
parameters through the getParameter() method. This method is part of
the Applet class.
- Here we present a modified init() method
for the Hello applet which gets the value to display from HTML
parameters. In this case, we look for the parameter named "text" and
pass the value to the constructor of the Text control:
public void init()
{
String text = null;
try { text = getParameter("text"); }
catch (Exception e) {}
if (text == null)
text = "<No text specified>";
setLayout(new BorderLayout());
add(new Text(text), "Center");
}
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