bootstrap引入后页面闪现后消失

用masterpage编写的页面，三板块，左侧是导航栏
导航栏.aspx 单独运行还可以完好无误跑出来
但是从mainpage进入就会出现左侧页面闪现一下，随后消失该页面页面代码如下（亲测不引用bootstrap比较丑的页面没有任何问题）：
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Left.aspx.cs" Inherits="Left" %><!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title></title>
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <!-- Bootstrap Styles-->
    <link href="assets/css/bootstrap.css" rel="stylesheet" />
    <!-- FontAwesome Styles-->
    <link href="assets/css/font-awesome.css" rel="stylesheet" />
    <!-- Morris Chart Styles-->
    <link href="assets/js/morris/morris-0.4.3.min.css" rel="stylesheet" />
    <!-- Custom Styles-->
    <link href="assets/css/custom-styles.css" rel="stylesheet" />
    <!-- Google Fonts
    <link href='https://fonts.googleapis.com/css?family=Open+Sans' rel='stylesheet' type='text/css' /> -->
    <link rel="stylesheet" href="assets/js/Lightweight-Chart/cssCharts.css" /> </head>
<body>
    <div id="wrapper">
        <nav class="navbar-default navbar-side" role="navigation">
            <div class="sidebar-collapse">
                <ul class="nav" id="main-menu">                    <li>
                        <a class="active-menu" href="#"><i class="fa fa-dashboard"></i> Dashboard</a>
                        <!-- mainpage opened -->
                    </li>
                    <li>
                        <a href="#"><i class="fa fa-sitemap"></i> ####<span class="fa arrow"></span></a>
                        <ul class="nav nav-second-level">
                            <li>
                                <a href="AddSample.aspx" target="showframe">###</a>
                            </li>
                            <li>
                                <a href="FindSample.aspx" target="showframe">###</a>
                            </li>
                        </ul>
                    </li>
                </ul>
            </div>        </nav>
    </div>
    <script src="assets/js/jquery-1.10.2.js" type="text/javascript"></script>
        <!-- Bootstrap Js -->
    <script src="assets/js/bootstrap.min.js"></script>
 
    <!-- Metis Menu Js -->
    <script src="assets/js/jquery.metisMenu.js"></script>    <!-- Morris Chart Js -->
    <script src="assets/js/morris/raphael-2.1.0.min.js"></script>
    <script src="assets/js/morris/morris.js"></script> 
<script src="assets/js/easypiechart.js"></script>
<script src="assets/js/easypiechart-data.js"></script>

 <script src="assets/js/Lightweight-Chart/jquery.chart.js"></script>
    <!-- Custom Js -->
    <script src="assets/js/custom-scripts.js"></script> 
</body>
</html>
求各位大神，研究一天，毫无进展