How to install prototype.js

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While using W3Schools, you agree to have read and accepted our terms of use , cookie and privacy policy. Copyright by Refsnes Data. Skip to content. Change Language. Related Articles. Table of Contents. Improve Article. Save Article. Like Article. Last Updated : 30 Jun, The prototype property allows to add new properties and methods to the existing JavaScript object types.

There are two examples to describe the JavaScript String prototype property. Syntax: object. As mentioned above, each object's prototype is linked to function's prototype object. If you change function's prototype then only new objects will be linked to changed prototype. All other existing objects will still link to old prototype of function. The following example demonstrates this scenario.

The prototype object is being used by JavaScript engine in two things, 1 to find properties and methods of an object 2 to implement inheritance in JavaScript. In the above example, toString method is not defined in Student, so how and from where it finds toString?

Here, prototype comes into picture. First of all, JavaScript engine checks whether toString method is attached to studObj? It is possible to attach a new function to a instance in JavaScript. If it still cannot find it there then it goes up in the heirarchy and check prototype object of Object function because all the objects are derived from Object in JavaScript, and look for toString method.

Thus, it finds toString method in the prototype object of Object function and so we can call studObj. This way, prototype is useful in keeping only one copy of functions for all the objects instances. C ASP. Skill Tests ASP.