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>