First, you're returning the function before it gets to display the value.
Second, as stated above, you can't use
Third, you're using global variables and that's messing up your function parameters with the same name. num1 and num2 are actually 'undefined' in your
Fourth, you're not calling
with any value. You need to pass the values into the function.
Fifth (and final), you're not adding the numbers.
returns a string, not a number. You're actually concatenating the input (making a string combining the 2 inputs, so if you enter 5 and 4, the result will be 54, not 9)
Check this out: http://jsfiddle.net/ACcGC/4/