计算字符串内的字出现几次

	// 创建一个字符串 
	var str = "adminadmiaaaanhelloworldhello",
		obj = {};
	console.log(str, obj)
	console.log(undefined + 1)
	// 开启循环处理字符串
	for (var i = 0; i < str.length; i++) {
		// str[i] --> str[0] = a --> obj[a]:10 
		// obj[a] = (obj[str[i]] + 1) || 1;
		// obj[a] = 1
		// obj[a] = (obj[str[i]] + 1) || 1;
		// console.log(obj[str[i]] )
		// obj[str[i]] = (obj[str[i]] + 1) || 1;

		// obj[str[i]] = 1;
		// key:value //左边的是key 右边的是value 赋值给key
		// obj[a] = obj[a]+1 ||1;
		obj[str[i]] = (obj[str[i]]) + 1 || 1
	}

	//

	// console.log(obj)
	// 对象.方法|属性 
	var v_json = JSON.stringify(obj); // 静态方法	
	console.log(v_json) // ->
	//{"a":6,"d":3,"m":2,"i":2,"n":2,"h":2,"e":2,"l":5,"o":3,"w":1,"r":1}