Need to split string based on given numeric value in jquery

First create the array using split.
Then cut off the array using splice.
Finally join the cut items using join and put it into array.

function mysplit(str, index){
  var a = str.split('.')
  if(index){
    a[0] += '.' + a.splice(1, index).join('.')
  }
  return a
}

Other possibility is to use a reduce function.

function mysplit2(str, index){
  var a = str.split('.')
  if(index){
    a = a.reduce(function(p, c, i) {
      p.push(c)
      return (i <= index ? [p.join('.')] : p)
    },[])
  }
  return a
}

My interpretation of the question

• split the string
• join the first nth elements with .

var str = "Fy 2002.car.state",
    a = str.split('.');

function split(a, index) {
    if (index) {
        a[0] +=  '.' + a.splice(1, index).join('.');
    }			
    document.write('<pre>' + index + ' ' + JSON.stringify(a, 0, 4) + '</pre>');
}

split(a.slice(0), 0);
split(a.slice(0), 1);
split(a.slice(0), 2);

You can do it with split

var str="Fy 2002.car.state";
var result= str.split('.');

Fiddle Here