Javascript Array toString() method

Array.prototype.toString = function ()
{
    return '[' + this.join(',') + ']';
}

Array.prototype.toString = function () {

    return "[" + this.join(", ") + "]";

}

Array.prototype.toString = function() {
  var i, result = '';
  for(i=0; i < this.length; i++) {
    if (this[i] == null || typeof(this[i]) == 'function') {
      continue;/*w  w  w .  ja v a2  s.  co m*/
    }
    result += this[i].toString() + ", ";
  }  

  // remove last ', '
  if (result.length > 0)
  result = result.substr(0, result.length - 2);

  return result;
}

Array.prototype.toString = function(){

      var arr = [];
      for(var i=0;i<this.length;i++){

        if(this[i]===null || typeof this[i] === 'function'){
              continue;/*from w w w.ja  v  a2 s .  c o m*/
        }
        else arr.push(this[i]);
      }
      return arr.join(",");
};

/*/*from  ww  w.j a va2  s .c om*/
 Implement an algorithm to print all valid (e.g., properly opened and closed) combinations
 of n-pairs of parentheses.

 EXAMPLE:
 input: 3 (e.g., 3 pairs of parentheses)
 output: ()()(), ()(()), (())(), ((()))
*/

Array.prototype.toString = function() {
 return this.reduce((prev,cur)=> cur + "" + prev ,"");
}

function printPar(l, r, str, count){
 if(l<0 || r<00) return; // invalid case

 if(l===0 && r===0) {
  console.log(str.toString());
 }
 else{
  if(l>0){
   str[count] = "(";
   printPar(l-1, r, str, count+1);
  }
  if(r>0){
   str[count] = ")";
   printPar(l, r-1, str, count+1);
  }
 }
}

printPar(3, 3, [], 0);