高效查找一个字符串中，出现次数最多的字符

//查找字符串中出现最多的字符  及次数-----------
//采用hash计数统计
function find(str) {
var hash = {},max = 0,c;
var length = str.length;
for(var i = 0;i<length;i++){
var char =str.charAt(i)
if(hash.hasOwnProperty(char)){
var count = hash[char]
}else{
count = 0;
}
hash[char] = ++count;
if(count>max){
max = count;
c = char;
}
}
return {"max":max,"char":c}
}
alert(find("adflaskdjflkjlaksdjflkasjdfkwj")["max"])

//采用splite
function find(str) {
var max = 0, c;
while(str) {
var char = str.charAt(0);
var a = str.split(char);
var count = str.length - (str = a.join("")).length;
if(count > max) {
max = count;
c = char;
}
}
return {"max":max, "char":c};
}

alert(find("adflaskdjflkjlaksdjflkasjdfkwj")["char"]);
        //采用replace函数
    var str= 'sjckjdsbkjcbsdjkbkjb';
    str = str.split('').sort().join('');
    var count = 0;
    var val;
    str.replace(/(\w)\1*/g,function(arg0,arg1){
if(arg0.length>count){
count = arg0.length;
val = arg0;
    }
        })