js怎么去判断两个字符串中相同元素并输出相同的元素？

Question

s1、s2为字符串类型，写一个函数返回s1、s2开头部分相同的字符数

Answer 1

function fiterStr(str1,str2){&nbsp; &nbsp; var l = str1.length > str2.length ? str2.length : str1.length, //取短的&nbsp; &nbsp; &nbsp; &nbsp; i = 0&nbsp; &nbsp; while(i < l){&nbsp; &nbsp; &nbsp; &nbsp; if(str1[i] !== str2[i])break&nbsp; &nbsp; &nbsp; &nbsp; i++&nbsp; &nbsp; }&nbsp; &nbsp; return str1.substr(0,i)}fiterStr('ssd','sss'); //'ss'

Answer 2

双for循环

Answer 3

请描述清楚问题什么叫开头部分相同的字符数?