Help subtracting two numbers and showing result in form field.

I am working on form. The following is just a part of the form. The user will enter two numbers say Num1 and Num2. I want to actively show the result in a readonly text field. How can I do this using javascript? There are other fields in the form too so I don't want to lose their value if I have to reload. Any help will be appreciated. I am also using cold fusion.

Thanks!

algomezAsked:
Who is Participating?
 
avnerConnect With a Mentor Commented:
Use this to make it work when you click anywhere on the screen :
<html>
<head>
<title>new Documet </title>
<script>
<!--(c)Avner Cohen [avcoh@yahoo.com]

-->
</script>
<style>

</style>
</head>

<body onclick="document.forms[0].value3.value=(document.forms[0].value1.value-document.forms[0].value2.value)">
<FORM>
<BR/>
Value 1 :<input type="text" name="value1" value="1111">
<BR/>Value 2 :<input type="text" name="value2" value="563">
<BR/>Result  :<input type="text" name="value3" value="" DISABLED="TRUE" READONLY="TRUE">

</body>
</html>
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avnerCommented:
<html>
<head>
<title>new Documet </title>
<script>
<!--(c)Avner Cohen [avcoh@yahoo.com]

-->
</script>
<style>

</style>
</head>

<body>
<FORM>
<BUTTON onclick="this.form.value3.value=(this.form.value1.value-this.form.value2.value)">Calculate</BUTTON><BR/>
Value 1 :<input type="text" name="value1" value="1111">
<BR/>Value 2 :<input type="text" name="value2" value="563">
<BR/>Result  :<input type="text" name="value3" value="" DISABLED="TRUE" READONLY="TRUE">

</body>
</html>
0
 
algomezAuthor Commented:
This is very close to what I want but is there a away to not have to use the button to get the answer? The reason being that this subtraction is just part of a bigger form with other text fields.  If I am the user I will enter a value in the first num field , then enter the second number and when I click anywhere else on the form the readonly field displays the answer...?

Thanks alot!!!
0
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algomezAuthor Commented:
This is very close to what I want but is there a away to not have to use the button to get the answer? The reason being that this subtraction is just part of a bigger form with other text fields.  If I am the user I will enter a value in the first num field , then enter the second number and when I click anywhere else on the form the readonly field displays the answer...?

Thanks alot!!!
0
 
algomezAuthor Commented:
This is very close to what I want but is there a away to not have to use the button to get the answer? The reason being that this subtraction is just part of a bigger form with other text fields.  If I am the user I will enter a value in the first num field , then enter the second number and when I click anywhere else on the form the readonly field displays the answer...?

Thanks alot!!!
0
 
algomezAuthor Commented:
Thanks! Exactly what I need!

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CFXPERTCommented:
Try this out:

<html>
<head>
     <title>Untitled</title>
<script language="javascript">
function subtract(){
result.value = (num1.value - num2.value)
}
</script>
</head>

<body>
num1:<input type="text" name="num1" value="0"><br>
num2:<input type="text" name="num2" onChange="subtract()" value="0"><br>
otherField:<input type="text" name="other" value="click here"><br>
result:<input type="text" readonly name="result">
</body>
</html>
0
 
CFXPERTCommented:
never mind.  I was typing while you must have accepted his answer.

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