JavaScript

Javascript functions can be written in a javascript file or directly in an HTML document.
In both cases, when they are defined, they need to be called in order to be executed.




 <html>
<head>
<style>
button {width:100px;
        height:55px;
        color:red;}
</style>

</head>
<body>
  <button  onclick="message();">PRESS</button>
<script type="text/javascript">
function message()
{
alert("This is simple function called message()");
}
</script>
</body>
</html>  
  

result:







<script>
function profession(name, object) {

  if (object == "truck") {
     return "driver";}
  
 if (object == "ship") {
     return "sailor";}
     
    if (object == "aeroplan") {
      return "pilot";}

    var struka="" + name + " is " + vehicle + ".";
  return struka;
}
    var bus=profession("Bob","aeroplan");
    document.getElementById("demo").innerHTML =bus;
</script>
 

result: