The instanceof operator is use to get 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. |
Return a Boolean
Returns a Boolean value that indicates whethor or not an object is an instance of a particular class.
Example
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.
}
obj = new Date();
document.write(objTest(obj));
|
 To run the code above, paste it into JavaScript Editor, and click the Execute button.
See also: Operator Precedence, Operator Summary |
