The instanceof operator in JavaScript returns a Boolean value indicating whether an object is an instanceof a particular class.

**Usage: **Result = object instanceof class Where result is a required option. Any variable. Object is required. Any object expression. Class is required. Any defined object class.

**instructions **The instanceof operator returns true if object is an instanceof class. Returns false if object is not an instance of the specified class, or if object is null.

**The instanceof operator in JavaScript **The following example illustrates the use of the instanceof operator.

function objTest(obj){
   var i, t, s = "";   //Create variables.
   t = new Array();   //Create an array.
   t["Date"] = Date;   //Populate the array.
   t["Object"] = Object;
   t["Array"] = Array;
      for (i in t)
      {
         if (obj instanceof t[i])   //Check obj's class.
         {
            s += "obj is an instance of " + i + "/n";
         }
         else
         {
            s += "obj is not an instance of " + i + "/n";
         }
   }
   return(s);   //Returns a string.
}
var obj = new Date();
response.write(objTest(obj));