Javascript - Functions

<script type="text/javascript">
<!--
function functionname(parameter-list)
{
  statements
}
//-->
</script>

<script type="text/javascript">
<!--
function sayHello()
{
   alert("Hello there");
}
//-->
</script>

<script type="text/javascript">
<!--
sayHello();
//-->
</script>

<script type="text/javascript">
<!--
function sayHello(name, age)
{
   alert( name + " is " + age + " years old.");
}
//-->
</script>

<script type="text/javascript">
<!--
sayHello('Zara', 7 );
//-->
</script>

<script type="text/javascript">
<!--
function concatenate(first, last)
{
   var full;

   full = first + last;
   return  full;
}
//-->
</script>

<script type="text/javascript">
<!--
   var result;
   result = concatenate('Zara', 'Ali');
   alert(result );
//-->
</script>