Getting started
First of all I would like to remind you that there is absolutely no way to protect your images as well as HTML, JavaScript and CSS source from stealing. Anything you can view in your browser can be saved on a user’s hard drive and “cut open”. One can encounter some difficulties with certain types of content (like Flash, Java applets or WMV with DRM protection), but at the end it all depends on the individual’s level of determination.
Data security on the other hand is entirely different topic which we won’t be discussing today.
The approach
You can execute JavaScript code on a page by typing “JavaScript: somecode;” in the browser’s address bar and hitting Enter.
The code will immediately execute as long as the syntax is correct. When assigning values you have to include the assignment within the void() method as in void(some_variable=some_value). Otherwise the browser will jump to a blank page and output the variable on that page. Remember that!