ECMAScript array method，兼容ie6-8

es5_Array

/** 
*   ES5中新增数组方法的兼容实现
*   method：// forEach map filter some every indexof lastindexof reduce reduceRight
*/
if(typeof Array.prototype.forEach != 'function'){
    Array.prototype.forEach = function(fn,context){
      if(typeof fn === 'function'){
        for(var i = 0,length = this.length; i<length; i++){
              fn.call(context,this[i],i,this);
        }
      }
    }
}


if(typeof Array.prototype.map != 'function'){
    Array.prototype.map = function(fn,context){
      var arr = [];
      if(typeof fn === 'function'){
        for(var i = 0,length = this.length;i < length; i++){
              arr.push(fn.call(context,this[i],i,this));
        }
      }
    }
}

if(typeof Array.prototype.filter != 'function'){
    Array.prototype.filter = function(fn,context){
      var arr = [];
      if(typeof fn === 'function'){
        for(var i = 0,length = this.length;i < length; i++){
              fn.call(context,this[i],i,this) && arr.push(this[k]);
        }
      }
    }
}

if(typeof Array.prototype.some != 'function'){
    Array.prototype.some = function(fn,context){
      var passed = false;
      if(typeof fn === 'function'){
        for(var i = 0,length = this.length;i < length; i++){
              if(passed) break;
              passed = !!fn.call(context,this[i],i,this);
        }
      }
      return passed;
    }
}

if(typeof Array.prototype.every != 'function'){
    Array.prototype.every = function(fn,context){
      var passed = true;
      if(typeof fn === 'function'){
        for(var i = 0,length = this.length;i < length; i++){
              if(passed === false) break;
              passed = !!fn.call(context,this[i],i,this);
        }
      }
      return passed;
    }
}

if (typeof Array.prototype.indexOf != "function") {
  Array.prototype.indexOf = function (searchElement, fromIndex) {
    var index = -1;
    fromIndex = fromIndex * 1 || 0;

    for (var k = 0, length = this.length; k < length; k++) {
      if (k >= fromIndex && this[k] === searchElement) {
          index = k;
          break;
      }
    }
    return index;
  };
}

if (typeof Array.prototype.lastIndexOf != "function") {
  Array.prototype.lastIndexOf = function (searchElement, fromIndex) {
    var index = -1, length = this.length;
    fromIndex = fromIndex * 1 || length - 1;

    for (var k = length - 1; k > -1; k-=1) {
        if (k <= fromIndex && this[k] === searchElement) {
            index = k;
            break;
        }
    }
    return index;
  };
}

if (typeof Array.prototype.reduce != "function") {
  Array.prototype.reduce = function (callback, initialValue ) {
     var previous = initialValue, k = 0, length = this.length;
     if (typeof initialValue === "undefined") {
        previous = this[0];
        k = 1;
     }
     
    if (typeof callback === "function") {
      for (k; k < length; k++) {
         this.hasOwnProperty(k) && (previous = callback(previous, this[k], k, this));
      }
    }
    return previous;
  };
}

if (typeof Array.prototype.reduceRight != "function") {
  Array.prototype.reduceRight = function (callback, initialValue ) {
    var length = this.length, k = length - 1, previous = initialValue;
    if (typeof initialValue === "undefined") {
        previous = this[length - 1];
        k--;
    }
    if (typeof callback === "function") {
       for (k; k > -1; k-=1) {          
          this.hasOwnProperty(k) && (previous = callback(previous, this[k], k, this));
       }
    }
    return previous;
  };
}