Void(0) is used to prevent the page from refreshing and parameter “zero” is passed while calling.

Void(0) is used to call another method without refreshing the page.

“==” checks only for equality in value whereas “===” is a stricter equality test and returns false if either the value or the type of the two variables are different.

In order to detect the operating system on the client machine, the navigator.appVersion string (property) should be used.

The NULL value is used to represent no value or no object.  It implies no object or null string, no valid boolean value, no number and no array object.

The functionality of delete operator is used to delete all variables and objects in a program but it cannot delete variables declared with VAR keyword.

Below given are the popup boxes supported by Javascript

• Alert
• Confirm and
• Prompt

Negative Infinity is a number in JavaScript which can be derived by dividing negative number by zero.

A prompt box is a box which allows the user to enter input by providing a text box.  Label and box will be provided to enter the text or number.

Global variables are those that are available throughout the length of the code, that is, these have no scope. The var keyword is used to declare a local variable or object. If the var keyword is omitted, a global variable is declared.

This’ keyword is used to point at the current object in the code. For instance: If the code is presently at an object created by the help of the ‘new’ keyword, then ‘this’ keyword will point to the object being created.