<style>
span{display: block;}/* 将span转成块状元素 */</style><body><input type="text" id="pass"/><input type="button" id="btn" value="验证密码强度"/><span></span></body><script>
var opass = document.getElementById("pass");
var obtn = document.getElementById("btn");
var ospan = document.querySelector("span");
obtn.onclick =function(){
var str = opass.value;if( str ===""){return;}//三个计数器,用来记录某种类型是否出现,0不出现,1出现
var a =0;
var b =0;
var c =0;//拿到每一个字符for(var i=0;i<str.length;i++){//是否出现数字if(str[i]>=0&& str[i]<=9){
a =1;}//是否出现字母if(str[i]>="a"&& str[i]<="z"|| str[i]>="A"&& str[i]<="Z"){
b =1;}//是否出现非数字或非字母if(!(str[i]>=0&& str[i]<=9|| str[i]>="a"&& str[i]<="z"|| str[i]>="A"&& str[i]<="Z")){
c =1;}}//遍历结束后,将所有的计数器累加,并判断switch(a + b + c){case1:
ospan.innerHTML ="简单";break;case2:
ospan.innerHTML ="一般";break;case3:
ospan.innerHTML ="困难";break;}}</script>