function this
Description
this is a reference to the function context object.
Example
When a function is called in the global scope of a web page, this points
to window.
<!-- ww w.ja v a 2 s . c o m-->
<!DOCTYPE HTML>
<html>
<head>
<script type="text/javascript">
window.myName = "XML";
function printMyName(){
console.log(this.myName);
}
printMyName(); //"XML"
var o = { myName: "HTML" };
o.printMyNameForMyObject = printMyName;
o.printMyNameForMyObject(); //"HTML"
</script>
</head>
<body>
</body>
</html>
Note
printMyName() is defined globally and references the this object.
this is not determined until the function is called.
When printMyName() is called in the global scope, it outputs "XML" because this is pointing to window, which means this.myName evaluates to window.myName.
By assigning the function to the object o and then calling o.printMyName(), the this object points to o, so this.myName evaluates to o.myName and "HTML" is displayed.