会员登录页面登录按钮不跳转

<div class="login-wrap">
          <form name="LoginForm" id="LoginForm" onsubmit="return false;">
                <p class="login-unit login-unit-user">
                    <label style="opacity: 1;" name="username" for="username" class="login-placeholder">帐号</label>
                    <input name="username" size="12" id="username" class="login-input login-acc" tabindex="1" type="text">
              </p>
                <p class="login-unit login-unit-pwd">
                    <label style="opacity: 1;" name="passwd" for="passwd" class="login-placeholder">密码</label>
                    <input name="passwd" size="13" id="passwd" class="login-input" tabindex="2" type="password">
                </p>
                <p class="login-unit login-unit-chk">
                    <label style="opacity: 1;" name="rmNum" for="rmNum" class="login-placeholder">验证码</label>
                    <input name="rmNum" id="rmNum" size="7" maxlength="4" class="login-input" tabindex="3" type="text" onfocus="getKey();document.getElementById('vPic').style.display='block'">
                    <img width="40" height="18" onclick="getKey();" id="vPic">
                </p>
                <p class="login-link-area">
                    <input value="" class="login-submit" tabindex="4" type="submit" name="formsub" onclick="aLeftForm1Sub();">
                    <a href="javascript:alert('请联系客服人员！');" class="forget-pwd-btn"></a>
                    <a id="textGlitter11" onclick="click_url('/wwwroot/myreg.php')" href="javascript:void(0);" class="join-btn"></a>
                </p>
         </form>
                  
            </div>点击登录按钮不跳转，不提交表单。