jQuery普遍运用于JAVA_WEB前端，可以说jQuery的运用无处不在，学好jQuery，对于一个程序员来说是必由之路。下面简单介绍一下jQuery实现密码强度检测。
如图所示：
核心代码：
第一步：css样式：
/** 清除内外边距 **/
body, h1, h2, h3, h4, h5, h6, hr, p,
blockquote, /* structural elements 结构元素 */
dl, dt, dd, ul, ol, li, /* list elements 列表元素 */
pre, /* text formatting elements 文本格式元素 */
form, fieldset, legend, button, input, textarea, /* form elements 表单元素 */
/* table elements 表格元素 */
img/* img elements 图片元素 */{
border:medium none;
margin: 0;
padding: 0;
}
input::-ms-clear{display:none;}
/** 设置默认字体 **/
body,button, input, select, textarea {
font-family:微软雅黑, Verdana, Geneva, sans-ser;
font-size:14px;
color:#666;}
h1, h2, h3, h4, h5, h6 { font-size: 100%; }
em{font-style:normal;}
/** 重置列表元素 **/
ul, ol, li { list-style: none outside; display:block; overflow:hidden; }
/** 重置超链接元素 **/
a { text-decoration: none; color:#333;}
/** 重置图片元素 **/
img{ border:0px;}
/** 重置表格元素 **/
/**************会员注册 start*********************/
.ywz_zhuce_wenzi{float:left; width:1000px; text-align:left; height:30px;line-height:30px; font-weight:bold; font-size:16px; color:#333; }
.ywz_zhuce_zou1{ float:left; width:1000px; height:690px; border:1px #dcdcdc solid;}
.ywz_zhuce_huanying{ float:left; width:600px; margin-left:61px; margin-top:36px; font-size:16px; font-weight:bold;color:#797979;}
.ywz_zhuce_bao{ float:left; width:640px; height:360px; padding: 30px 0px 0px 66px; border-right:1px dashed #e5e5e5;}
.ywz_zhucexiaobo{ float:left; width:620px; padding-bottom:10px;padding-top:5px; margin-left:20px;}
.ywz_zhuce_youjian{ float:left; width:100px; margin: 5px 0 0 0; font-size:14px; text-align:right; }/*用户*/
.ywz_hong{ color:#ff4e00; font-size:12px; font-family:"宋体";}/*加红*/
.ywz_zhuce_kuangzi{ float:left; width:226px; height:38px; color:#171717;}
.ywz_zhuce_kuangwenzi2{float:left; color:#3e3e3e; width:210px; height:36px; border: 1px solid #C4C4C4; padding:0 15px 0 15px; line-height:35px; _padding-left:20px;outline:medium;}
.ywz_zhuce_kuangwenzib{float:left; border: 1px solid #C4C4C4; color:#3e3e3e; width:210px; height:36px; padding: 0 15px 0 15px; line-height:35px; _padding-left:20px;outline:medium;}
.ywz_zhuce_input{float:left; color:#3e3e3e; width:126px; height:36px; border:0; padding-left:25px; line-height:35px; _padding-left:20px;outline:medium; border-left: 1px solid #c4c4c4; border-top: 1px solid #c4c4c4;border-bottom: 1px solid #ebebeb; border-right: 1px solid #ebebeb; line-height:36px; color:#b6b6b6;}
.ywz_zhuce_yuo{ float:right; width:240px; margin-top:60px;}
.ywz_zhuce_yongkuang1{ font-size:16px; font-weight:bold; color:#010101; clear:both; text-align:left; text-indent:22px;}
.ywz_zhuce_hongkuang{ float:left; margin-top:15px; background:#fe7213;}
.ywz_zhuce_hongkuang a{ float:left; font-size:14px; background: #A2A2A2; width:137px; height:34px; font-weight:bold; color:#FFF; line-height:34px;}
.ywz_zhuce_hongkuang a:hover{ float:left; background: #C00; width:137px; height:34px; color:#FFF; }
.ywz_zhuce_denglusanjiao{ float:left; margin-top:12px; margin-left:35px; color:#fff;}
.ywz_zhuce_muqian{ float:left; width:205px; margin-top:30px; font-size:12px; color:#666; text-align:left;}
.ywz_zhuce_hongzi{ color:#ff6701;}
.ywz_zhuce_kuangwenzi3{ float:left; background: url(../images/zhuce_kuang_03.jpg) no-repeat; border:0; color:#3e3e3e; width:222px; height:30px; padding-left:2px; padding-top:12px;}
.ywz_tc_dl{ float:left; background:url(../images/denglu-yaoshi_03.jpg) no-repeat; width:20px; height:30px;}
.ywz_zhuce_yongyu{ float:left; color:#468e9d; font-size:12px; padding-left:15px; margin-top:10px; _padding-left:5px; }/*后面的文字*/
.ywz_zhuce_yongyu a{ color:#468e9d; }
.ywz_zhuce_yongyu a:hover{ color:#468e9d; text-decoration:underline;}
.ywz_zhuce_yongyu1{ float:left; color: #C00 ; font-size:12px; padding-left:10px; margin-top:10px; _padding-left:0px; }/*后面的文字*/
.ywz_zhuce_yongyu1 a{ color:#C00; text-decoration:none; }
.ywz_zhuce_yongyu1 a:hover{ color:#C00; }
.ywz_zhuce_xiaoxiaobao{ float:left; width:226px; }
.ywz_zhuce_hongxian{ float:left; background:#ff3300; width:62px; height:4px; margin-top:5px; margin-left:5px; _margin-top:0px;_height:2px; font-size:0px;}
.ywz_zhuce_hongxian2{ float:left; background: #099; width:62px; height:4px; margin-top:5px; margin-left:5px; _margin-top:0px;_height:2px; font-size:0px;}
.ywz_zhuce_hongxian3{ float:left; background: #060; width:62px; height:4px; margin-top:5px; margin-left:5px; _margin-top:0px;_height:2px; font-size:0px;}
.ywz_zhuce_huixian{ float:left; background:#d6d3d3; width:62px; height:4px; margin-top:5px; _margin-top:0px; margin-left:5px; _height:2px;font-size:0px;}
.ywz_zhuce_hongxianwenzi{ float:left; width:62px; margin-left:5px; text-align:center; color:#b0adad; font-size:12px; }
.ywz_zhuce_tongyi{ float: right; width:530px; margin-bottom:10px; }/*同意内面*/
.ywz_zhuce_dui{ float:left; width:10px; height:10px;}
.ywz_zhuce_tongyiwenzi{ float:left; font-size:12px; color:#555; padding-bottom:10px;}/*同意*/
.ywz_zhuce_lanseai{ color:#1190ae;}
.ywz_jhbg1{ background: url(../images/DENGSE_03.jpg) no-repeat center top; width:7px; height:12px; _padding-top:5px; _height:2px; _font-size:0px; *height:16px; display: inline-block; }
.ywz_zhuce_bgkuang{float:right; width:520px; text-align:center;}
.ywz_zhuce_tijiao{ float:left; background:#e6343c; width:200px; height:40px; }
.ywz_zhuce_tijiao a{ float:left; background: #e6343c; width:2020px; height:40px; color:#FFF; font-size:16px; line-height:40px; }
.ywz_zhuce_tijiao a:hover{ float:left; background:#d52028; width:200px; height:40px; }
.ywz_zhuce_zhujiwenzi{ float:left; font-size:18px; font-weight:bold; color:#fff; padding-left:55px; padding-top:15px;}
.register_hy2{ margin-top: 6px; float:left; height:30px; line-height:30px !important; font-family:微软雅黑,Verdana, Geneva, sans-serif;}
/*弹窗注册*/
.reg_succes1 a{ color:#FFF; line-height:26px;}
/*人头*/
.ywz_zhuce_kuangwenzi{ float:left; background: url(../images/deng1.jpg) no-repeat; border:0; color:#3e3e3e; width:221px; height:40px; line-height:35px; padding-left:25px; _padding-left:20px; outline:medium; }
/*邮箱*/
.ywz_zhuce_kuangwenzi0{ float:left; background: url(../images/zhuce_kuang_03.jpg) no-repeat; border:0; color:#3e3e3e; width:220px; height:35px; line-height:35px; padding-left:5px; _padding-left:7px;outline:medium;}
/*钥匙*/
.ywz_zhuce_kuangwenzi1{ float:left; background: url(../images/dengl_06.jpg) no-repeat; border:0; color:#3e3e3e; width:210px; height:40px; line-height:35px; padding-left:25px; _padding-left:20px;outline:medium;}/*框*/
.ywz_zhuce_denglu{ float:left; color:#468e9d; font-size:12px; padding-top:10px; padding-left:15px; _padding-left:0px;}
.ywz_zhuce_denglu a{ color:#468e9d; }
.ywz_zhuce_denglu a:hover{ color:#468e9d; text-decoration: underline;}
.ywz_zhuce_denglulo{ float:left; width:110px; color:#949494; margin-top:15px; font-size:12px; }
.ywz_zhuce_denglu1{ color:#468e9d; font-size:12px; }
.ywz_zhuce_denglu1 a{ color:#468e9d; }
.ywz_zhuce_denglu1 a:hover{ color:#468e9d; text-decoration: underline;}
.ywz_zhuce_denglukuang{ float:left; width:500px; margin-top:0px;height:40px; text-align:center;}
.dcdl{width:500px; background:#e6343c; width:182px; height:40px; line-height:40px;text-align:center; color:#fff; font-size:16px; font-weight:bold; border:none;}
.dcdl:hover{ background:#c1171f;}
.ywz_zhuce_kuangzilu{ float:left; width:105px;}
.ywz_zhuce_kuangzidenglu{ float:left; background: url(../images/dengloo_03.jpg) no-repeat; border:0px; color:#3e3e3e; width:120px; height:37px; line-height:30px; padding-left:5px;outline:medium;}/*验证码*/
.ywz_denglu_yanzheng{ float:left; margin-left:15px; padding-left:8px; _margin-left:1px; _padding-left:2px; }
.ywz_zhuce_dengbao{ float:left; width:640px; height:280px; padding: 30px 0px 0px 66px; border-right:1px dashed #e5e5e5;}
第二步：导入图片images
第三步：导入js标签库（同时导入JQuery.min）
$('#tbPassword').focus(function () {
$('#pwdLevel_1').attr('class', 'ywz_zhuce_hongxian');
$('#tbPassword').keyup();
});
$('#tbPassword').keyup(function () {
var __th = $(this);
if (!__th.val()) {
$('#pwd_tip').hide();
$('#pwd_err').show();
Primary();
return;
}
if (__th.val().length < 6) {
$('#pwd_tip').hide();
$('#pwd_err').show();
Weak();
return;
}
var _r = checkPassword(__th);
if (_r < 1) {
$('#pwd_tip').hide();
$('#pwd_err').show();
Primary();
return;
}
if (_r > 0 && _r < 2) {
Weak();
} else if (_r >= 2 && _r < 4) {
Medium();
} else if (_r >= 4) {
Tough();
}
$('#pwd_tip').hide();
$('#pwd_err').hide();
});
function Primary() {
$('#pwdLevel_1').attr('class', 'ywz_zhuce_huixian');
$('#pwdLevel_2').attr('class', 'ywz_zhuce_huixian');
$('#pwdLevel_3').attr('class', 'ywz_zhuce_huixian');
}
function Weak() {
$('#pwdLevel_1').attr('class', 'ywz_zhuce_hongxian');
$('#pwdLevel_2').attr('class', 'ywz_zhuce_huixian');
$('#pwdLevel_3').attr('class', 'ywz_zhuce_huixian');
}
function Medium() {
$('#pwdLevel_1').attr('class', 'ywz_zhuce_hongxian');
$('#pwdLevel_2').attr('class', 'ywz_zhuce_hongxian2');
$('#pwdLevel_3').attr('class', 'ywz_zhuce_huixian');
}
function Tough() {
$('#pwdLevel_1').attr('class', 'ywz_zhuce_hongxian');
$('#pwdLevel_2').attr('class', 'ywz_zhuce_hongxian2');
$('#pwdLevel_3').attr('class', 'ywz_zhuce_hongxian3');
}
function checkPassword(pwdinput) {
var maths, smalls, bigs, corps, cat, num;
var str = $(pwdinput).val()
var len = str.length;
var cat = /.{16}/g
if (len == 0) return 1;
if (len > 16) { $(pwdinput).val(str.match(cat)[0]); }
cat = /.*[\u4e00-\u9fa5]+.*$/
if (cat.test(str)) {
return -1;
}
cat = /\d/;
var maths = cat.test(str);
cat = /[a-z]/;
var smalls = cat.test(str);
cat = /[A-Z]/;
var bigs = cat.test(str);
var corps = corpses(pwdinput);
var num = maths + smalls + bigs + corps;
if (len < 6) { return 1; }
if (len >= 6 && len <= 8) {
if (num == 1) return 1;
if (num == 2 || num == 3) return 2;
if (num == 4) return 3;
}
if (len > 8 && len <= 11) {
if (num == 1) return 2;
if (num == 2) return 3;
if (num == 3) return 4;
if (num == 4) return 5;
}
if (len > 11) {
if (num == 1) return 3;
if (num == 2) return 4;
if (num > 2) return 5;
}
}
function corpses(pwdinput) {
var cat = /./g
var str = $(pwdinput).val();
var sz = str.match(cat)
for (var i = 0; i < sz.length; i++) {
cat = /\d/;
maths_01 = cat.test(sz[i]);
cat = /[a-z]/;
smalls_01 = cat.test(sz[i]);
cat = /[A-Z]/;
bigs_01 = cat.test(sz[i]);
if (!maths_01 && !smalls_01 && !bigs_01) { return true; }
}
return false;
}
来源：https://www.cnblogs.com/wlx520/p/4677472.html