Expert Developer JavaScript Interview Preparation Guide

isNan function returns true if the argument is not a number otherwise it is false.

Netscape is the software company who developed JavaScript.

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.

// for Single line comments and

/* Multi

Line

Comment

*/

=== is called as strict equality operator which returns true when the two operands are having the same value without any type conversion.

Since 3 and 2 are integers, they will be added numerically. And since 7 is a string, its concatenation will be done. So the result would be 57.

Undefined value means the

► Variable used in the code doesn't exist
► Variable is not assigned to any value
► Property doesn't exist

Escape characters (Backslash) is used when working with special characters like single quotes, double quotes, apostrophes and ampersands. Place backslash before the characters to make it display.

Example:

document.write "I m a "good" boy"

document.write "I m a "good" boy"

'Typeof' is an operator which is used to return a string description of the type of a variable.

JavaScript is a client-side scripting language that can be inserted into HTML pages and is understood by web browsers.