Javascript Numbers

Numbers or integers are whole numbers or fractional numbers. Numbers can be added, subtracted, multiplied and divided, thus perform all arithmetic operations.


 var a=3;    	    // number; 
 var b=3.6;         // number with decimal; 
 var c=0xa;         // number in hexadecimal 
 var d=010;         // number in octal
 var e=0b100;       // number in binary
 var f=Infinity;    // number more than 10308 
 


Methods of Numbers

MethoduseExample
toString()convert number to string.var x=6;
x.toString()="6";
toLocalString()convert number to local string.var x=6;
x.toLocalString()="6";
toExponential()convert decimal to exponential notation.var x=6;
x.toExponential()="6e+0";
toPrecision(1)convert number to Precise .var x=1.23456;
x.toPrecision(1)="1";
toPrecision(2)convert decimal to exponential notation.var x=1.23456;
x.toPrecision(2)="1.2";
toPrecision(3)convert decimal to exponential notation.var x=1.23456;
x.toPrecision(3)="1.23";

String to Number conversion

Javascript variables can be strings or numbers. Like var x="5" is string, but var y=5 is number. But both can be used in arithmetic operations. Except addition, all arithmetic operations are possible with x and y.


	var x="5";		// string
	var y=5;		// number
	
	x+x="55";		// concat
	y+y=10;			// addition
	x+y="55"		// concat, as x is string
	
	x-x=0;			// subtraction
	y-y=0;			// subtraction
	x-y=0;			// subtraction
	
	x*x=25;			// multiplication
	y*y=25;			// multiplication
	x*y=25;			// multiplication
	
	x/x=1;			// division
	y/y=1;			// division
	x/y=1;			// division
	
	x%x=0;			// modulus
	y%y=0;			// modulus
	x%y=0;			// modulus
	

Three functions to convert string to number.

  • Number()
  • parseInt()
  • parseFloat()

Number Function

Number Function can convert string to numbers.


    var a="100";
    var b="100.5";
    var c="100px";
    var d="abc100";
    
    Number(a)       //100
    Number(b)       //100.5
    Number(c)       //NaN - Not a Number
    Number(d)       //NaN - Not a Number
    

parseInt Function

parseInt Function can convert string to numbers, but non floating values only.


    var a="100";
    var b="100.5";
    var c="100px";
    var d="abc100";
    
    parseInt(a)       //100
    parseInt(a,2)     //4, binary number
    parseInt(a,8)     //64, octal number
    parseInt(a,16)    //256, octal number
    parseInt(b)       //100
    parseInt(c)       //100
    parseFloat(d)     //NaN - Not a Number
    

parseFloat Function

parseFloat Function can convert string to numbers, floating and non floating both.


    var a="100";
    var b="100.5";
    var c="100px";
    var d="abc100";
    
    parseFloat(a)       //100
    parseFloat(b)       //100.5
    parseFloat(c)       //100
    parseFloat(d)       //NaN - Not a Number
    

"+" operator and "concat()" method, both concat strings in javascript.