判断一个字符串中出现次数最多的字符，统计这个次数

var str = "abcdefgaaaaaaddda";

var obj = {};

var arr = [];

var letter;

for(var i = 0,len = str.length;i<len;i++){

letter = str[i];

if(!obj[letter]){

obj[letter] = 1;

}else{

obj[letter]++;

}

}

 

var max_key,max_num=0;

for(key in obj){

if(max_num <obj[key]){

max_num = obj[key];

max_key = key;

}

}

document.write("字母："+max_key+"　次数："+max_num);