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How Do I keep from getting this "NaN" in blank fields

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rampage60

rampage60

IS-IT--Management
Jul 1, 2002
73
NO
How do I keep from getting the "NaN" in the fields if I don't fill out all of the fields. Thanks!

<html>
<head>
</head>

<body>
<p>Mileage Report</p>
<SCRIPT LANGUAGE=&quot;javascript&quot;>
function add()
{
var sum01 = document.george.start01.value;
var sum02 = document.george.finish01.value;
var sum = parseInt(sum02) - parseInt(sum01);
document.george.total01.value = sum;

var sum03 = document.george.start02.value;
var sum04 = document.george.finish02.value;
var suma = parseInt(sum04) - parseInt(sum03);
document.george.total02.value = suma;

var sum05 = document.george.start03.value;
var sum06 = document.george.finish03.value;
var sumb = parseInt(sum06) - parseInt(sum05);
document.george.total03.value = sumb;

document.george.gross.value = sum + suma + sumb;
}
</script>

<div align=&quot;center&quot;><form name=&quot;george&quot;>


Start <input type=text name=&quot;start01&quot; size=&quot;4&quot;>
Finish <input type=text name=&quot;finish01&quot; size=&quot;4&quot;>
Total <input type=text name=&quot;total01&quot; size=&quot;4&quot; readonly=&quot;&quot;>
<br>
Start <input type=text name=&quot;start02&quot; size=&quot;4&quot;>
Finish <input type=text name=&quot;finish02&quot; size=&quot;4&quot;>
Total <input type=text name=&quot;total02&quot; size=&quot;4&quot; readonly=&quot;&quot;>
<br>
Start <input type=text name=&quot;start03&quot; size=&quot;4&quot;>
Finish <input type=text name=&quot;finish03&quot; size=&quot;4&quot;>
Total <input type=text name=&quot;total03&quot; size=&quot;4&quot; readonly=&quot;&quot;><br>

Gross <input type=text name=&quot;gross&quot; size=&quot;4&quot;><br>

<p><input type=&quot;button&quot; value=&quot;Do It&quot; onClick=&quot;add()&quot;></div></p>
</form>

</body>
</html>
 
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loop through the fields and give a value of 0 to them if empty. seeing as you are not validating the fields for a empty value this would be the easy solution
eg:
for (x = 0; x <= MyForm.length; x++) {
if(document.MyForm.elements[x].type==&quot;text&quot;){
//add another condition for further checking what fields to set
document.MyForm.elements[x].value = 0
}

other then that you could just add to your script some validation prior to setting the var's
if(document.george.start01.value==&quot;&quot;) {
document.george.start01.value= 0

or check the vars in the same way.

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Where you get the values for the calculations, you need to validate what is in the fields before performing numeric operations on them. (By the way 'NaN' stands for Not a Number)

If you don't put a value (or put a text value) in any of your fields, the parseInt() function will return NaN because, obviously, an empty string or a string containing alpha characters is not a number.

To perform some validation you should check the values after getting them out of the fields but before running parseInt() over them. To check for a numeric value you can make use of the isNaN(value) function. isNaN() returns true or false depending on whether the tested value is not, or is a number. You can use the output of isNaN() in an if() statement to validate your form input as in the following example:
[tt]
var sum01 = document.george.start01.value;
if(isNaN(sum01)){
sum01 = 0;
}
var sum02 = document.george.finish01.value;
if(isNaN(sum02)){
sum02 = 0;
}
var sum = parseInt(sum02) - parseInt(sum01);
document.george.total01.value = sum;
[/tt]

This will ensure that the operands are always numbers by the time you try to add them together.
 
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