Web修改密码功能

<input style="float: right;margin-right: 50px;margin-bottom: 10px;margin-top: 0px;" data-toggle="modal" data-target="#updatePassword"  class="btn btn-primary" type="button" value="修改密码" />
                <!-- 模态框（Modal） -->
                <div class="modal fade" id="updatePassword" tabindex="-1" role="dialog" aria-labelledby="myModalLabel" aria-hidden="true">
                    <div class="modal-dialog">
                        <div class="modal-content">
                            <div id="updatePassword" style="margin-top: 15px" >  <img alt="update" src="<%=request.getContextPath()%>/resources/image/userMgr/update.png">  <label>密码修改</label></div>   
                            <hr>
                            
                            <form name="pwd_change_form" action="${pageContext.request.contextPath}/asset/user/updatePassword?userId=${sessionScope.loginUser.userId }" method="post">                                                      
                            <div id="userInfo" class="modal-body">
                                <table>
                                    <tr>                    
                                        <td><input type="hidden" name="holdPassword"  value =${sessionScope.loginUser.password } /></td>
                                        <td><input type="hidden" name="userName"  value =${sessionScope.loginUser.userName } /></td>    
                                    </tr>
                                    <tr>                    
                                        <td>旧    密   码: <input placeholder="密码长度为5~16" minlength="5" maxlength="16"  type="password" name="oldPassword"  id="oldPassword"/></td>    
                                    </tr>
                                    <tr>                    
                                        <td>新    密   码: <input placeholder="密码长度为5~16" minlength="5" maxlength="16"  type="password" name="newPassword"  id="newPassword"/></td>
                                    </tr>
                                    <tr>
                                        <td>确认新密码: <input placeholder="密码长度为5~16" minlength="5" maxlength="16" type="password" name="password"  id="password"/></td>                                                                                                                                                                                                                
                                    </tr>
                                </table>
                            </div>              
                            <div class="modal-footer">
                                <input type="button" data-dismiss="modal" style="width:110px;height:40px; background: url('<%=request.getContextPath()%>/resources/image/userMgr/cancel.png');"/>
                                <input type="submit" onClick="return checkForm(pwd_change_form)" style="width:110px;height:40px; background: url('<%=request.getContextPath()%>/resources/image/userMgr/save.png');" name="updatePassword" value=""/>
                            </div>
                            </form>
                        </div>
                    </div>
                </div>  

在body中写:

<script type="text/javascript" src="${pageContext.request.contextPath}/resources/js/md5.js" ></script>
<script language="javascript">
    function checkForm(form){
        if(form.oldPassword.value==""){
            alert("请输入的原密码!");
            form.oldPassword.focus();
            return false;
        }
        if(md5(form.oldPassword.value)!=form.holdPassword.value){
            alert("您输入的原密码不正确，请重新输入!");
            form.oldPassword.value="";
            form.oldPassword.focus();
            return false;
        }
        if(form.newPassword.value==""){
            alert("请输入的新密码!");
            form.newPassword.focus();
            return false;
        }
        if(form.password.value==""){
            alert("请确认新密码!");
            form.password.focus();
            return false;
        }
        if(form.newPassword.value!=form.password.value){
            alert("您输入的新密码不一致，请重新输入!");
            form.newPassword.value="";
            form.password.value="";
            form.newPassword.focus();
            return false;
        }
    }
</script>

MD5加密方法参考：
http://www.bootcdn.cn/blueimp-md5/
https://github.com/blueimp/JavaScript-MD5