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Ajtolie · 04-08-2014, 04:17 AM

Below is my Javascript math program. I'm not sure what I am doing wrong but it will not function properly. Please help!

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html>

<head>
<title>JavaScript Functions</title>

<script type="text/javascript">
var num1 = 0;//acts as a place holder for the user number
var num2 = 0;//acts as a place holder for the user's second number
var calculatedNum = 0;//place holder for the user's answer

function calculation() {
// type your calculation and output statements here
calculatedNum = num1 * num2;//equation for the user's two numbers//holds user's first number and second number, then multiplies them together
num1 = prompt("Please type the first number");//prompt asking for the user's first number
num2 = prompt("Please type the second number");//prompt asking for the user's second number

alert( num1 + " x " + num2 + " is " + calculatedNum + " ! " );
} // end calculation function

</script>

</head>

<body>

<h1></h1>

</body>
</html>

? · 04-08-2014, 04:25 AM

Try wrapping the num's in a parseInt()
Or parseFloat.

Check the users input if it contains only number.
Turn ',' into '.'

Next times, tell what the output is or what happens when it goes wrong.
Like, where you getting only "NaN"? //Not a number
Or did you get "null" //user hit cancel

Dominic · 04-08-2014, 04:30 AM

The order that things is a bit mixed up. Prompt the user. Then do the calculation. Finally, show the result.

- Dominic

siteman · 04-08-2014, 04:38 AM

javascript reads from top to bottom. your variables were out of order. I fixed this. I also added a button so you can test that the function works, and the button can be easily removed if desired.

<html>

<head>
<title>JavaScript Functions</title>

<script type="text/javascript">
var num1 = 0;//acts as a place holder for the user number
var num2 = 0;//acts as a place holder for the user's second number
var calculatedNum = 0;//place holder for the user's answer

function calculation() {
// type your calculation and output statements here
num1 = prompt("Please type the first number");//prompt asking for the user's first number
num2 = prompt("Please type the second number");//prompt asking for the user's second number
calculatedNum = num1 * num2;//equation for the user's two numbers//holds user's first number and second number, then multiplies them together
alert( num1 + " x " + num2 + " is " + calculatedNum + " ! " );
} // end calculation function

</script>

</head>

<body>
<button onClick="calculation()">test it.</button>
<h1></h1>

</body>
</html>