js实现登录页面的背景图片的随机展示

版权声明:本文为博主原创文章,转载请注明出处。 https://blog.csdn.net/ItChuangyi/article/details/80727632

js代码如下:

<script type="text/javascript">
        // 随机展示背景图片 
        var imgSrcs = [ "${ctx}/static/images/background/1.jpg",
                "${ctx}/static/images/background/2.jpg",
                "${ctx}/static/images/background/3.jpg",
                "${ctx}/static/images/background/4.jpg" ];
        var randomBgIndex = parseInt(Math.random() * (imgSrcs.length));

        $(document).ready(
                function() {
                    $("body").css("background-image","url(" + imgSrcs[randomBgIndex] + ")");
                });
    </script>

login.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<%@ page trimDirectiveWhitespaces="true"%>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
<%@ taglib prefix="fmt" uri="http://java.sun.com/jsp/jstl/fmt"%>
<%@ taglib prefix="fn" uri="http://java.sun.com/jsp/jstl/functions"%>
<c:set var="ctx" value="${pageContext.request.contextPath}"/>
<!-- <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> -->
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8"/>
    <meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1"/>
    <meta name="viewport" content="width=device-width, initial-scale=1"/>
    <title>Teacher-登录</title>

    <link rel="stylesheet" href="${ctx}/css/bootstrap.css" />
    <link rel="stylesheet" href="${ctx}/css/login.css" />
    <script type="text/javascript" src="${ctx}/js/jquery-1.11.3.min.js"></script>
    <script type="text/javascript" src="${ctx}/js/bootstrap.js"></script>

    <script type="text/javascript">
        // 随机展示背景图片 
        var imgSrcs = [ "${ctx}/images/background/1.jpg",
                "${ctx}/images/background/2.jpg",
                "${ctx}/images/background/3.jpg",
                "${ctx}/images/background/4.jpg" ];
        var randomBgIndex = parseInt(Math.random() * (imgSrcs.length));
        $(document).ready(
                function() {
                    $("body").css("background-image","url(" + imgSrcs[randomBgIndex] + ")");
                });

        // 判断是登录账号和密码是否为空
        function checkForm(){
            var usercode = $("#usercode").val();
            var password = $("#password").val();
            if(usercode=="" || password==""){
                $("#message").text("账号或密码不能为空!");
                return false;
            }  
            return true;
        }
    </script>
</head>

<body>
    <div class="container">
        <div class="top_div"></div>

        <div class="login">
            <form action="${pageContext.request.contextPath }/login.action"
                method="post" onsubmit="return checkForm()">
                <div style="float: left; padding: 20px 10px 0px 40px;">
                    <h4>
                        用户登录
                    </h4>
                </div>

                <div style="padding: 70px 0px 10px; position: relative;">
                    <span class="glyphicon glyphicon-user" aria-hidden="true"
                        style="padding: 10px 10px;"></span> <input id="usercode"
                        name="usercode" class="ipt" type="text" placeholder="输入用户名" 
                        value="">
                </div>
                <div style="padding: 20px 0px 10px;" position:relative;">
                    <span class="glyphicon glyphicon-lock" aria-hidden="true"
                        style="padding: 10px 10px;"></span> <input id="password"
                        name="password" class="ipt" type="password" placeholder="输入密码"
                        value="">
                </div>
                <div style="height: 5px">
                    <font color="red">
                            <span id="message">
                                ${msg }
                            </span>
                    </font>
                </div>
                <div
                    style="height: 60px; line-height: 50px; margin-top: 30px; border-top-color: rgb(231, 231, 231); border-top-width: 1px; border-top-style: solid;">
                    <div style="margin: 0px 35px 10px 45px;">
                        <span style="float: center; padding: 25px 20px;">
                            没有账号?<a href="${ctx }/toRegister.action" >注册</a>一个吧
                        </span>
                        <span style="float: right; padding: 15px 20px;"> <input
                            type="submit" class="btn btn-success border" value="登录" />
                        </span>
                    </div>
                </div>
            </form>
        </div>
        <div class="bottom_div"></div>
    </div>
</body>
</html>

页面显示效果

这里写图片描述

这里写图片描述

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转载自blog.csdn.net/ItChuangyi/article/details/80727632