types of Pop up boxes available :

escape() :
The escape () function is responsible for coding a string to transfer the information from one computer to the other across a network.
EX :
(script>
document.write(escape("Hello? How are you!"));
(/script>
Output: Hello%3F%20How%20are%20you%21

unescape() :
The unescape() function is very important as it decodes the coded string. It works in the following way. For example:
EX :
(script>
document.write(unescape("Hello%3F%20How%20are%20you%21"));
(/script>
Output: Hello? How are you!