See Also

Description

Returns a Boolean value that indicates whethor or not an object is an instance of a particular class.

Syntax

result = object instanceof class

The instanceof operator syntax has these parts:

Part	Description
result	Any variable.
object	Any object expression.
class	Any defined object class.

Remarks

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

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 class of obj.
      {
        s += "obj is an instance of " + i + "\n";
      }
      else 
      {
        s += "obj is not an instance of " + i + "\n";
      }
  }
  return(s);                   // Return string.
}  

var obj = new Date();
response.write(objTest(obj));