如何在Bootstrap模态框内加载表单

Question

我想在bootstrap模式框中加载 upload.php ，这是我的代码

  <h4>Update Database</h4>
  	<div class="btn-group btn-group-justified">
  <div type="button" class="btn btn-success" data-toggle="modal" data-target="#myModal">Update</div>
	</div>
  <div class="modal fade" id="myModal" role="dialog">
    <div class="modal-dialog modal-lg">
      <div class="modal-content">
        <div class="modal-header">
          <button type="button" class="close" data-dismiss="modal">&times;</button>
          <h4 class="modal-title">Step One 1</h4>
        </div>
        <div class="modal-body">
			<form id="upload" method="post" action="upload.php" enctype="multipart/form-data">
			<div id="drop">
			Update DB
				<button>Upload</button>	
			</div>
			<ul>
         	</ul>
			</form>
        </div>
        <div class="modal-footer">
          <button type="button" class="btn btn-default" data-dismiss="modal">Close</button>
        </div>
      </div>
    </div>
  </div>

但是当我点击上传按钮时，该页面会重定向到 upload.php

  

如何在点击上传按钮后将其加载到模态框内？

提前致谢