the same function can be used as static, or as constructor, or as a method

comments	Javascript source	Execution result in your current browser
define a global function	function Rect(w, h) { this.width=w; this.height=h document.write("this="+this); }
call it as static function	Rect(2,3); //call as static function, "this" inside would be global/window //same this, inside or outside function document.write("<br/>width="+width);
call it as constructor	var sq=new Rect(20,30);//this is object function(Class) instance document.write("<br/> the value of width="+sq.width); document.write("<br/> the value of global width="+width);

comments

Javascript source

Execution result in your current browser

define a global function

  function Rect(w, h) {

    this.width=w;
    this.height=h
    document.write("this="+this);
  }

call it as static function

   Rect(2,3); //call as static function, "this" inside would be global/window
   //same this, inside or outside function
   document.write("<br/>width="+width);

call it as constructor

    var sq=new Rect(20,30);//this is object function(Class) instance
   document.write("<br/> the value of width="+sq.width);
   document.write("<br/> the value of global width="+width);