A _javascript technique for acquiring the JS function of the nth element node

A function to get the nth element node, which is now only available through the HTML tag, and the function is not perfect.

Demo: HTML

<ul id= "List" >
<li>1<button>a</button></li>
<li>2<button>b </button><button>o</button></li>
<p>test</p>
<li>3<button >c</button></li>
<li>4<button>d</button></li>
<li>5< Button>e</button></li>
</ul>

Js:

/** * @param Parent parent node * @param ele the element label to select * @param num the first few elements * @return {*}/function Nth (parent,ele,num) {var _ele=a
Rray.prototype.slice.call (Parent.childnodes), elearray=[];
Converts a child node of a parent node to an array of _ele;elearray for only the element nodes (Var i= 0,len=_ele.length;i<len;i++) {if (_ele[i].nodetype==1) { Elearray.push (_ele[i])//filter out non-element nodes} if (arguments.length===2) {//If only 2 parameters are passed in, if the second argument is a number, select the first element under the parent node//If the second argument is a string , select all the parameters under the parent node to represent the node if (typeof arguments[1]=== "string") {_ele=array.prototype.slice.call (
Parent.getelementsbytagname (arguments[1]));
return _ele; }else if (typeof arguments[1]=== "number") {return elearray[arguments[1]];} else{//If the parameter is complete, return the first few nodes, the index starting from 0 _ele=array.prototype.slice.call (Parent.getelementsbytagname (ele));
];
}/* Test * * var List=document.getelementbyid ("list");
Console.log (Nth (list, "Li", 2). InnerHTML)//Select the third Li element Console.log (nth (List, button, 3). InnerHTML)//Select the fourth button Console.log (Nth (nth (list, "Li", 1), "button", 1);//Select the second button under the second Li Console.log (nth (list,Li ", 1)," button ");//Select All buttons under the second Li Console.log (nth (list,2)), or select the second element