Multiplying two textbox values

#1
njr1489

Posted 24 February 2009 - 06:35 PM

Learning Programmer

Members
70 posts

I am trying to calculate two values that a user would input in two text boxes. With my current code throws an exception because of the the assignment of total. I'm not really sure how else I could go about doing this... This is the current code I have.

<html>
<head>
<script>
var total = document.frm.len.value * document.frm.wid.value;

function calculate()
{
     alert(total);
}
</script>
</head>
<body>

<form name="frm">
<table>
<tr>
<td>Length</td>
<td><input type="text" name="len" /></td>
</tr>

<tr>
<td>Width</td>
<td><input type="text" name="wid" /></td>
</tr>

<tr>
<td><input type="button" name="Submit" value="Submit" onClick="calculate()" /></td>
</tr>
</table>
</form>

</body>
</html>

---------------------------------------------------------------------------

EDIT:

I got it, here's the results for those of you that want it:

<html>
<head>
<script>

function calculate(length, width)
{
     alert(length.value * width.value);
}
</script>
</head>
<body>

<form name="frm">
<table>
<tr>
<td>Length</td>
<td><input type="text" name="len" /></td>
</tr>

<tr>
<td>Width</td>
<td><input type="text" name="wid" /></td>
</tr>

<tr>
<td><input type="button" name="Submit" value="Submit" onClick="calculate(document.frm.len, document.frm.wid)" 

/></td>
</tr>
</table>
</form>

</body>
</html>

Edited by njr1489, 24 February 2009 - 07:35 PM.
Figured it out myself.

#2
Brandon W

Posted 24 February 2009 - 11:33 PM

Writes binary right handed and hex left handed

Members
4,828 posts

I was just about to say something along those lines. Good work mate :)

Thanks for posting the final code too mate, this will help people with the same problem.

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Sorry if I don't post as often as I did, I'll try to get here as much as possible! I'm working my bum off to get this scholarship and other stuff!

#3
CameronMauch

Posted 31 March 2009 - 06:05 AM

Newbie

Members
3 posts

njr1489 said:


<html>

<head>

<script>

var total = document.frm.len.value * document.frm.wid.value;


function calculate()

{

     alert(total);

}

</script>

</head>

<body>


<form name="frm">

<table>

<tr>

<td>Length</td>

<td><input type="text" name="len" /></td>

</tr>


<tr>

<td>Width</td>

<td><input type="text" name="wid" /></td>

</tr>


<tr>

<td><input type="button" name="Submit" value="Submit" onClick="calculate()" /></td>

</tr>

</table>

</form>


</body>

</html>

---------------------------------------------------------------------------

EDIT:

I got it, here's the results for those of you that want it:


<html>

<head>

<script>


function calculate(length, width)

{

     alert(length.value * width.value);

}

</script>

</head>

<body>


<form name="frm">

<table>

<tr>

<td>Length</td>

<td><input type="text" name="len" /></td>

</tr>


<tr>

<td>Width</td>

<td><input type="text" name="wid" /></td>

</tr>


<tr>

<td><input type="button" name="Submit" value="Submit" onClick="calculate(document.frm.len, document.frm.wid)" 


/></td>

</tr>

</table>

</form>


</body>

</html>

The reason you saw an exception was probably because the javascript began executing before the page had finished loading. The two input elements may not have existed yet. Use <body onload="..."> or the superior jQuery $(document).ready().

Cameron