IE 5.5: Formatting, URIs, and Stack Operations : Detecting Object-Property Ownership
IE 5.5: Formatting, URIs, and Stack Operations
Detecting Object-Property Ownership
IE5.5 introduced a score of new operators and methods for detecting various object-property relationships. The
in operator checks if a given property is defined for a given object. Suppose the object
line is of type
line = new Array("aaa", "bbb", "ccc", "ddd", "eee");
We know that the object
line inherited the Array's properties such as its
length. If we check whether
length is in
length in line), we should get a true value.
Notice that the array should not be empty, or else the returned answer will be a false value.
Similarly, the method
hasOwnProperty does exactly what the
in operator does. The expression
line.hasOwnProperty(length) should return a true value.
propertyIsEnumerable() checks, again, that the given property belongs to the given object. Once it belongs, every property is automatically enumerable in the
for...in loops. The
for...in loop loops through the existing properties of a given object. The check
line.propertyIsEnumerable(length) should return a true value.
Next: How to encode and decode URIs
Produced by Yehuda Shiran and Tomer Shiran
Created: March 14, 2000
Revised: April 26, 2000