Today,I started to code a page that prompt
the user to choose their PC spec,and
the code is as follow
<html>
<title>Computer Specification Chooser</title>
<head>
<script type="text/javascript">
var compSpec = document.compChooser;
function processorUnavailable_onclick()
{
alert("Sorry that processor speed is currently unavailable");
compSpec.processor[2].checked = true;
}
</script>
</head>
<body>
<form name="compChooser">
<p>Tick all components you wan included on your computer</p>
<p>
DVD-ROM
<input type="checkbox" name="chkDVD" value="DVD-ROM" />
<br />
CD-ROM
<input type="checkbox" name="chkCD" value="CD-ROM" />
<br />
Zip Drive
<input type="checkbox" name="chkZIP" value="ZIP DRIVE" />
</p>
<p>
Select
the processor speed you require
<br />
<input type="radio" name="processor" value="3.8" />
3.8 GHZ
<input type="radio" name="processor" value="4.8" onclick="processorUnavailable_onclick()" />
4.8 GHZ
<input type="radio" name="processor" value="6" />
6 GHZ
</p>
<input type="button" name="btnCheck" value="Check Form" />
</form>
</body>
</html>
The problem I'm facing is on
the function that I've tie to
the event handler,when I try to choose
the radio button of
the processor value 4.8 GHZ,yes it alert me with
the message inside
the function,but after that,it doest not execute
the next statement inside
the function,that is to check
the next processor value 6 GHZ,I've try my effort to change it and test on it,and find out when I set
the var compSpec = document.compChooser as a local variable inside
the function instead of a global variable,
the next statement could be executed.But I thought for a global variable,it is accessible in everywhere on
the page and also inside a function.But why now I can't accesses it inside my function??Any idea??Besides,I stumble upon a weird article while googling,it says that when a global variable is created,it is added to window object.I just curious why this happen??And what's
the benefits and uses of it??THANK YOU
