查找数组中某个元素出现的次数（以apple为例）
var arr = ['apple', 'banana', 'peach', 'apple', 'pear' ,'apple'];
var index = arr.indexOf('apple');
var count = 0;
while(index !== -1){
count ++;
console.log(index);
index = arr.indexOf('apple', index + 1);
}
console.log('apple出现次数为：' + count);
Yheyi-javascript👣
