Calling a javascript function Problem

quinnd6 · 01-03-2007 1:21am #1

I dont know how to use this java script function within a html page.

<script type = "text/javascript">
function Prod(a,b)
{
x= a*b;
return x;

}

</script>

I tried

<html>
<head>
<script type = "text/javascript">
function Prod(a,b)
{
x= a*b;
return x;

}

</script>

</head>
<body>

<script type ="text/javascript">
var a =10;
var b=20;
c = prod(10,20)
document.write("HEYY"+ c)

</script>

</body>
</html>

How do I get an html Page to display the result of the function ie. to display the product of two numbers from a javascript function?

smcelhinney · 01-03-2007 9:52am

Small point quinn. Use the code brackets when displaying code, its easier for us to read.

Is this script not working? It may work in IE because ie being non-standards based is a little forgiving when it comes to XML and javascript. If the code above appears like that in the browser then there are a couple of issues

1) HTML attributes shouldnt have whitespace. eg. <script type="text/javascript">
2) You should declare (var) all variables. eg var c = prod(10,20), otherwise, how is the compiler supposed to know what they are? cmon..
3) Javascript is case sensitive. eg prod(a,b) is NOT the same as Prod(a,b)
4) Terminate all javascript code blocks with a semicolon. eg. document.write("HEYY"+c);

If you have copied and pasted this from your code, then the above 4 reasons will (depending on your browser) cause your script to fail. If you try it all within one code block on the page as such.

<script type = "text/javascript">

function prod(a,b) {
var x= a*b;
return x;
}

var a = 10;
var b = 20;
var c = prod(a,b); // why did you have prod(10,20) here?! makes no sense!
document.write("HEYY"+ c);

</script>

HTH,
Stephen

NutJob · 01-03-2007 10:14am

Use the Dom to append it to a Div

eg

[php]

<script type = "text/javascript">

function WriteText(){
var output = "this should work";

document.getElementById("Output").innerText = output;
}

window.onload = WriteText();
}

<BODY>
.
.. lots of html type stuff
...

<DIV id="Output"></div>
[/php]

2) You should declare (var) all variables. eg var c = prod(10,20), otherwise, how is the compiler supposed to know what they are? cmon..

Itll work its just not a great idea. Simply because javascript excutes as the doc is read. Use Onload as this allows the documet to finish loading before running javascript so that it doesnt get funny errors if tags havnt loaded in time.

If your learning javascript download

http://www.getfirebug.com/
http://www.mozilla.org/projects/venkman/
http://chrispederick.com/work/webdeveloper/

thell help alot

quinnd6 · 01-03-2007 8:22pm

Excellent thanks guys for all the info.
It works now after your help
The Problem was I was calling prod instead of Prod(I didnt spot that myself).
Thanks

Calling a javascript function Problem

Comments