Processing Function Output

2. Printing a function output

          To print an output of a function, we can use the different I/O statements discussed in Module 8.4 (Basic Statements: I/O Statements).  Suppose that we have a code of a function that computes the sum of two numbers below. The output of this function is the sum of the two inputs.

function getSum(a, b){
 sum = a + b;
}

          If we want to print the sum of the two numbers, we can do so by adding an I/O statement within the function block. The code below shows an example of printing the sum inside an HTML element.

<div id="div1"> </div>
<script>
 function getSum(a, b){
	 sum = a + b;
	 document.getElementById('div1').innerHTML = sum;
 }
 getSum(1,2);
</script>

          This next block of code shows how to display the output of the function using an alert box.

<script>
 function getSum(a, b){
          sum = a + b;
          window.alert(sum);  
 }
</script>

          With the two methods learned, notice that the output is accessed only within the function block. Remember that variables created inside the function block are local variables – this means that they can only be accessed within that block. When you try to access that variable outside the function, it will give an undefined value.