Adding up the fields to make 100% in a form

[gayeta]

Hi

I wondered whether someone can point me to a script which would perform a simple calculation.

In this survey i have created
http://www.altassets.com/surveysmade...2008survey.php

in point 4b
----------------------------
b.) What do you anticipate will be your allocation split between re-ups and new investment in funds in 2008?



Re-ups (textfield name: ReupsSplitPercentage) %

New (textfield name: NewSplitPercentage) %

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


I need to make sure that the two fields do not add up to more than a 100%. If one number is entered the other gets automaticly adjusted. Alternatively I could add a Total field which would be a sum of the two, and which would display an error message when the sum is bigger than 100%.


At the moment both fields have for a simple validation applied where either can be heigher than 100.


I am a bit of a novice in java script , any help would be very much appreciated...


Many thanks in advance!!

Gayeta

[gimbles]

so based on your code, here's an idea:

<script type="text/javascript">
adjustPercent = function(aVal) {
	var val = ['ReupsSplitPercentage', 'NewSplitPercentage'];
 
 
	var v1 = document.getElementById(val[aVal]);
	var v2 = document.getElementById(val[1-aVal]);
 
	if(isNaN(v1.value))
		return false;
 
	v2.value = 100-v1.value;
}
</script>
 
	<td width="235" height="30" align="left" valign="middle"> <b>Re-ups</b>                          <label>
	  <input name="ReupsSplitPercentage" type="text" class="text" id="ReupsSplitPercentage" onBlur="adjustPercent(0)" size="5">
	  %</label></td>
	<td width="365" align="left" valign="middle">
	<b>New</b>                        
	<label><input name="NewSplitPercentage" type="text" class="text" id="NewSplitPercentage" onBlur="adjustPercent(1)" size="5">
	%</label>                        <br>                        </td>

that doesnt check for percentages higher than 100, just resets the other percentage, should get you started