实现效果

HTML
<!-- 验证密码强度S -->
<div class="pswContainer">
<h1>验证密码强度</h1>
<label for="">密码</label>
<input type="text" id="inp1" maxlength="16">
<div class="pass_wrap">
<em>密码强度:</em>
<em id="strength">高</em>
<div id="strengthLevel" class="strengthLv0"></div>
</div>
</div>
<!-- 验证密码强度E -->
CSS
/* 验证密码强度S */
.strengthLv1 {
background-color: red;
height: 6px;
width: 40px;
border: 1px solid #ccc;
padding: 2px;
}
.strengthLv2 {
background-color: blue;
height: 6px;
width: 80px;
border: 1px solid #ccc;
padding: 2px;
}
.strengthLv3 {
background-color: green;
height: 6px;
width: 120px;
border: 1px solid #ccc;
padding: 2px;
}
/* 验证密码强度E */
JS
// 验证密码强度S
// 有小写字母,数字,其他字符,级别+1
var inp1 = document.getElementById("inp1");
var strength = document.getElementById("strength");
var strengthLevel = document.getElementById("strengthLevel");
var arr = ["", "低", "中", "高"];
inp1.onkeyup = function () {
// 获取用户输入内容
// 记录安全级别
var level = 0;
// 正则表达式判断输入的东西
// 小写字母,级别+1
if (/[a-z]/.test(this.value)) {
level++;
}
// 数字+1
if (/[0-9]/.test(this.value)) {
level++;
}
// 其他+1
if (/[^a-z0-9]/.test(this.value)) {
level++;
}
strength.innerHTML = arr[level];
strengthLevel.className = "strengthLv" + level;
};
// 验证密码强度E