Search for the maximum number of occurrences of a character in a string, the most frequently occurring character, and the index of the character with the most occurrences

<! DOCTYPE html>
Css.css
div {    width:800px;    height:200px;    Background: #f1f1f1;    margin:0 Auto;    Text-align:center;    line-height:20px;    border:1px solid #ccc;    border-radius:10px;} h2 {    font-size:20px;    width:100%;} button {    cursor:pointer;    Background: #eee;    border:1px solid #ddd;} input {    width:165px;    height:25px;    border:1px solid #ddd;}
Js.js
Window.onload = function () {var obtn = document.getelementsbytagname ("button");    var oipt = document.getelementsbytagname ("input");        Obtn[0].onclick = function () {var str = oipt[0].value;        var Objchar = {};            for (var i = 0; i < str.length; i++) {var char = Str.charat (i);            if (Objchar[char]) {Objchar[char] + = 1;            } else {Objchar[char] = 1;        }} var maxCount = 0;        var maxcharindex = [];                for (var key in Objchar) {if (MaxCount < Objchar[key]) {maxCount = Objchar[key];                Maxcharindex = [];            Maxcharindex.push (key);            } else if (MaxCount = = Objchar[key]) {Maxcharindex.push (key);        }} function GetCount () {return maxCount;        } function Getmaxchar () {return maxcharindex;        } var objindex = {}; var maxindex= []; for (var j = 0; J < Maxcharindex.length, J + +) {for (var i = 0; i < str.length; i++) {if (Str[i] = = Maxcharindex[j])                {Maxindex.push (i);                    } if (i = = str.length-1) {Objindex[maxcharindex[j]] = Maxindex;                Maxindex = [];            }}} function GetIndex () {var maxIndex2 = [];            for (var key in Objindex) {Maxindex2.push (key +) is indexed ("+ Objindex[key] +") ";        } return MAXINDEX2;        } Oipt[1].value = GetCount ();        Oipt[2].value = Getmaxchar ();    Oipt[3].value = GetIndex (); }}
　　
Search for the maximum number of occurrences of a character in a string, the most frequently occurring character, and the index of the character with the most occurrences