typeof usage in JS

The variables in JS are loosely typed (i.e., weakly typed) and can be used to hold any type of data.

typeof can be used to detect the data type of a given variable, the possible return value:

1. ' Undefined '---this value is undefined;

2. ' Boolean '---This value is a Boolean value;

3. ' String '---This value is a string;

4. ' Number '---this value is numeric;

5. ' Object '---This value is an object or null;

6. The ' function '---this value is a functional.

JS Code:

var aa = ' test string ';   Alert (typeof AA);  // ' string '    alert (typeof );  // ' number '  

typeof usage in JS