Why Selenium scripts fail when run outside the web server for Selenium Core?

Hi All,

As we know selenium scripts will fail when we place our scripts outside the AUT (Application Under Test) web server for Selenium Core, this is due to the reason that Selenium core is built with DHTML / JavaScript. When we are using javaScript we should bound to Same Origin Policy of JavaScript.

What is Same Origin Policy?

Same origin Policy states that javaScript is only allowed to read / Modify the HTML content from the same origin as source i.e, javaScript can able to read / Modify the HTML only when the source and destination of the scripts are from same web server.

For Example:

Suppose a person is working on crutial page and some unsecured webpage simultaneously which are from different sources. If JavaScript is not bound to same Origin Policy, then the other user / Owner of unsecured web page can access / Modify the content of crutial web page. In order to avoid this JavaScript should be bound to Same Origin Policy.

But when we install Selenium IDE, this acts as a trusted FireFox extension and therefore we can violate the Same Origin Policy.