Explain advantages of DOM extension over VO extension?

In this article we shall discuss the advantages DOM has over VO. First, we shall discuss about these two silk test browser extensions individually. 

About VO Extension

- VO browser extension is related to the concept of virtual object. 

- An extension is a supplementary add–on component required for carrying out certain tests for web sites and web applications using silk test. 

- This virtual browser extension operates using a technique called the “sophisticated pattern recognition technique”.

- This technique helps in facilitating the object identification process and provides an actual view of the web sites and web applications.

- However, the HTML tags cannot be recognized with the help of this extension. - One thing to be noted is that only the objects present in the web pages can be recognized by the virtual object browser extension. 

- This extension however does not care about the implementation of these objects. 

- Identification of the object is done based up on the following:

1. Control type
2. Caption
3. Associated text
4. Control index
5. Location and
6. Window ID

- This browser extension is one of the methods used by the silk test for object recognition. 

About DOM Extension

- The second method is the Document Object Model and makes use of the DOM browser extension. 

- DOM browser extension is basically used for establishing a direct communication between the web application and web browser.

- The following tasks can be carried out:

1. Recognition of the objects
2. Categorization of the objects and
3. Manipulation of the objects

- The DOM browser extensions works with the HTML code rather than working up on the visual patterns like the virtual browser extension does.

- Firstly, it identifies the browser window of the application which consists of the application that is currently being executed. 

- The object among the other web UI objects is identified based unique HTML elements that represent that particular UI object. 

- This is done by concatenating the following two things:

1. HTML element identification and
2. Browser window identification

- This DOM browser extension is known to operate on the standards laid down by the W3C or world wide web consortium.

- However, till date there are only two browsers which support this extension namely internet explorer 5+ versions and netscape 6. 

- These two web browsers provide the provision to silk test for making direct queries to them.

Advantages of DOM over VO

Now let us see what all advantages DOM has got over the VO browser extension:

1. A rectangle is displayed over the VO or virtual object by the recorder as the recording is carried out by the quality assurance engineer.
2. The text size as well as the actual name of the objects is easily recognized by the DOM extension as compared with the VO browser extension.
3. The DOM extension is not dependent on the text size setting and browser size like the VO browser.
4. DOM extension provides a better support to the border-less tables.
5. More classes and properties are available in DOM extension as compared to the VO browser extension.
6. Using DOM extension, you can maintain a great consistency over the object recognition process.
7. DOM extension is quite fast in working as compared to the slow VO browser extension.
8. One can expect some gain in the playback speed in DOM extension but the same is not possible with the VO browser extension.
9. There is less crashing or freezing events in the recorder with the DOM extension and more in the VO browser extension.
10. In VO browser extension the conversion of scripts is more like a daunting task but this not so with DOM.