1<html>
2 <head>
3 <script>
4 function concatenate(name, age) {
5 var val;
6 val = name + age;
7 return val;
8 }
9 function DisplayFunction() {
10 var result;
11 result = concatenate('John ', 20) ;
12 document.write (result );
13 }
14 </script>
15 </head>
16 <body>
17 <p>Click the following button to call the function</p>
18
19 <form>
20 <input type = "button" onclick = "DisplayFunction()" value = "Result">
21 </form>
22 </body>
23</html>