An object method for an array
concat()
Usage: to connect two or more arrays, and returns the result.
Parameters: may be a single or a plurality of elements, may be one or more arrays may be mixed and used.
Returns: Returns an array of post-splicing.
Features: Does not change the original array.
Precautions: Su parameters passed though an array, but the operation is an array of elements inside.
join()
Usage: put all the elements of the array into a string. Elements separated by the specified delimiter.
Parameters: specified symbol for each element in the array is connected, the default is a comma.
Return Value: string splicing.
Features: Does not change the original array.
Precautions: toString () function and join the same time does not pass parameters, separated by commas default.
pop()
Usage: Removes and returns the last element of the array.
Parameters: No parameters, as specified delete the last.
Return Value: The return value to delete that element.
Features: change the original array.
push()
Usage: add one or more elements to the end of the array, and returns the new length.
Parameters: You can be one, multiple, add elements to the array represents the inside, the first parameter is required.
Return Value: to add a new value of the specified array length of the array.
Features: directly change the original array.
reverse()
Usage: reverse the order of elements in the array.
Parameters: No parameters.
Return Value: returns an array of the elements in reverse order.
Features: change the original array.
shift()
Usage: Remove the first item in the array.
Parameters: No parameters, because the first designated deletion.
Return Value: The return value to delete that element.
Features: change the original array.
unshift()
Usage: add one or more elements to the beginning of an array and returns the new length.
Parameters: may be one, may be a plurality, showing the beginning of the add elements to the array, the first parameter required.
Return Value: to add a new value of the specified array length of the array.
Features: change the original array.
slice()
Usage: Returns selected elements from an existing array.
Parameters: two parameters, where the first predetermined start (0 is the first), from the back, if the start is negative (-1 is the last, and so on). The second parameter determines where to stop, counting with a parameter. The first parameter required, the second parameter can be omitted, omit the second argument began to intercept correspondence from the end of the array.
Return Value: returns the value of those elements taken.
Features: Does not change the original array.
sort()
Usage: The element of the array is sorted.
参数：可选。规定排序顺序。必须是函数。
返回值：排序后的数组。
特点：改变原数组。
splice()
用法：删除元素，并向数组添加新元素。(增加、删除、修改数组任意位置元素)。
参数：多个参数，第一个参数规定了从哪个索引开始操作(可为负值，从-1开始代表最后一个)，第二个参数规定了从第一个参数对应的索引删除几个元素(为零则不删除)，第三个及以后的参数规定了添加的元素。前两个参数必须，第三及以后的参数可选。
返回值：删除的元素的值。
特点：改变原数组。
indexOf()
用法：返回某个指定的字符串值在字符串中首次出现的位置。
参数：两个参数，第一个参数规定了需检索的字符串值。第二个参数规定在字符串中开始检索的位置(合法值为对应数组下标的范围内的值)。第一个参数必需，第二个参数可选。
返回值：某个指定的字符串值在字符串中首次出现的位置(若没有出现则返回-1)。
特点：不改变原数组。