Javascript removes deplicates in an array

Javascript removes deplicates in an array

 Below is a sample code: 

01	Array.prototype.delRepeat=function(){

02	var newArray=new Array();

03	var len=this.length;

04	for (var i=0;i<len ;i++){

05	for(var j=i+1;j<len;j++){

06	if(this[i]===this[j]){

07

j=++i;

08

}

09

}

10	newArray.push(this[i]);

11

}

12	return newArray;

13

}

Obviously, there are two 'for' in this code snippet, which makes it very inefficient. Here is a more efficient one: 

 

01	Array.prototype.delRepeat=function(){

02	var newArray=[];

03	var provisionalTable = {};

04	for (var i = 0, item; (item= this[i]) != null; i++) {

05	if (!provisionalTable[item]) {

06	newArray.push(item);

07	provisionalTable[item] = true;

08

}

09

}

10	return newArray;

11

}