通过使用form的onsibmit来控制是否提交数据
返回值为真是提交，其他不变，示例如下：
JS部分
function check() { ???????????????????var newPwd = document.getElementById("newPwd"); ???????????????????var confirmNewPwd = document.getElementById("confirmNewPwd"); ???????????????????if (newPwd.value == confirmNewPwd.value) ???????????????????????return true; ???????????????????else { ???????????????????????var err = document.getElementById("errMSG"); ???????????????????????err.style.display = ""; ???????????????????????return false; ???????????????????} ???????????????}html
<form ?action="/student/UpdatePwd" onsubmit="return check()"> ???????????????<div class="control-group"> ???????????????????<label class="control-label" for="basicinput">旧密码</label> ???????????????????<div class="controls"> ???????????????????????<input placeholder="请输入…" data-original-title="" class="span8 tip" type="password" name="oldPwd" id="oldPwd"> ???????????????????</div> ???????????????</div> ???????????????<div class="control-group"> ???????????????????<label class="control-label" for="basicinput">新密码</label> ???????????????????<div class="controls"> ???????????????????????<input placeholder="请输入…" data-original-title="" class="span8 tip" type="password" name="newPwd" id="newPwd"> ???????????????????????<span class="help-inline" style="color:red;display:none" id="errMSG">两次密码不一致</span> ???????????????????</div> ???????????????</div> ???????????????<div class="control-group"> ???????????????????<label class="control-label" for="basicinput">再次输入新密码</label> ???????????????????<div class="controls"> ???????????????????????<input placeholder="请输入…" data-original-title="" class="span8 tip" type="password" id="confirmNewPwd"> ???????????????????</div> ???????????????</div> ???????????????<div class="control-group"> ???????????????????<div class="controls "> ???????????????????????<button type="submit" class="btn-inverse btn-large">更新</button> ???????????????????</div> ???????????????</div> ???????????</form>
html js 表单提交前检测数据
原文地址：http://www.cnblogs.com/ives/p/8025607.html