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Javascript - Text Fields that perform addition |
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Written by jose javier velez colon
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Wednesday, 24 June 2009 19:26 |
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>JJVC Javascript Form</title>
<script type="text/javascript">
function disableFields()
{
document.add.result.disabled=true;
}
function isNumeric(number,number2,number3){
if (isNaN(number) == true || isNaN(number2) == true || isNaN(number3) == true)//isNaN returns true if the input is not a number otherwise false.
{
alert("Only numbers are allowed as inputs");
return false;// one of the the values is not a number
}
else
{
return true;//all values are numbers
}
}
function validate()
{
/*this function attempts to validate the inputs from the form called add*/
var firstNumber = document.add.fnumber.value;
var secondNumber = document.add.snumber.value;
var thirdNumber = document.add.tnumber.value;
if (firstNumber =="" ||secondNumber=="" || thirdNumber =="" || thirdNumber == null || secondNumber == null || firstNumber == null ) {
alert("All text boxes must be filled");
//checking if all boxes are numbers
return false;
}
var secondTest = isNumeric(firstNumber,secondNumber , thirdNumber )
if(secondTest == true)//if all values are numbers then perform the addition
{
var result= eval(firstNumber) + eval(secondNumber) + eval(thirdNumber);//force javascript to recognize as number (eval function will work as well)
document.add.result.value=result;
}
return secondTest;
}
</script>
</head>
<body onload="disableFields()"><!--disables the result field-->
<form name="add" method="post">
<input type="text" name="fnumber"/>
+
<input type="text" name="snumber"/>
+
<input type="text" name="tnumber"/>
=
<input type="text" name="result"/>
<input type="button" value="add" onclick = "return validate()"/>
</form>
</body>
</html> |
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Last Updated on Wednesday, 24 June 2009 19:32 |