typeof operator in javascript!!

The typeof operator in javascript is used to find the data type of the variables or operands. typeof returns a string which includes any one of the below list.

• number: it returns this string if the input to the typeof is number
• string: it returns this string if the input to the typeof is string
• boolean: it returns this string if the input to the typeof is boolean
• The string is boolean and not bool
• object: it returns this string if the input to the typeof is javascript
• undefined: it returns this string if the input to the typeof is a variable and which is not defined

Syntax:

      typeof operand   // braces are optional
      typeof(operand)

Example:

       typeof 2 //returns number
       typeof(2) //returns number
       typeof("2") // returns string
       typeof(a) // a is a variable and returns depending on a value

Sample code:

function typetest()
{
 var a = 2; //number type
 var a = "2"; // string type
 var a;  //undefined
 var a =  true; //boolean type
 var a =  {a:"first character",b:"second character"}; // object type

 if(typeof a == "number")
  alert("a is number");
 else if(typeof a == "string")
  alert ("a is string");
 else if(typeof a == "undefined")
  alert ("a is undefined"); 
 else if(typeof a == "boolean")
  alert ("a is boolean"); 
 else if(typeof a == "object")
  alert ("a is object");  
}

This function gives object as output, because javascript overrides the variable declarations, so latest declaration will take, here it is javascript object. This variable overriding is called variable hoist. I will write one post on this later.

wamp server asking password in xp

Recently when I try to start the wamp server in my freinds laptop I faced this problem. And sharing the solution for that problem here.

The reason for this may be because of running IIS server in your system. To solve this problem either disable the IIS server. Follow below steps to disable IIS server.

1. Goto control panel
2. Goto Add/Remove programs
3. Goto Add/Remove Windows components
4. Uncheck IIS

Then restart the wamp server. This time it wont ask for the password.