js 合并两个数组，去除重复项，只留一个

    //It's merge arr1 and arr2 , delete the same element only leave one
    //It's only apdapter array. If object, no.
    //The sequence of the two array is not required.
    mergeArray:function (arr1, arr2){
  for (var i = 0 ; i < arr1.length ; i ++ ){
      for(var j = 0 ; j < arr2.length ; j ++ ){
       if (arr1[i] === arr2[j]){
         arr1.splice(i,1); //利用splice函数删除元素，从第i个位置，截取长度为1的元素
    }
      }
  }
  //alert(arr1.length)
  for(var i = 0; i <arr2.length; i++){
   arr1.push(arr2[i]);
  }
  return arr1;
 }

另：前替是两个数组中的项没有重复，如果重复，将不能达到想要的效果