js隔几秒刷新一次,怎么刷新不了

<html>
<head>
<title>Untitled Document</title>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312"><link rel="stylesheet" href="/SWebHQ/Css/Style1/webhq.css" type="text/css">
<script language="JavaScript1.2" src="/SWebHQ/JScript/Style1/webhq.js">
</script>
<script language="JavaScript1.2" src="/SWebHQ/JScript/Style1/hisdata.js">
</script>
<script language="JavaScript1.2" src="<#ModuleName>/HisData?Stkcode=<#Stkcode>&Style=<#Style>&CodeIndex=<#CodeIndex>">
</script>
</head><body bgcolor="#000000" text="#FFFFFF" leftmargin="0" topmargin="0" onkeydown="key();" onLoad="Calc();cmdfocus();" onhelp="javascript:return false">
<div id="Line" style="position:absolute; left:0px; top:0px; width:1px; height:379px; z-index:1; background-color: #FF0000; border: 1px none #000000; display: none"></div>
<div id="LayData" style="position:absolute; left:231px; top:90px; width:75px; height:94px; z-index:2; display: none"> 
  <table width="100%" border="1" cellspacing="1" cellpadding="3" height="94" id="TableData" bgcolor="#FFFFFF" bordercolor="#000000">
    <tr>
      <td>&nbsp;</td>
    </tr>
  </table>
</div>
<div id="test">
<table border="0" cellspacing="0" cellpadding="0">
  <tr>
<td><img id="Img" onMouseMove="ImgMove();" onMouseOut="ImgOut();" src="<#ModuleName>/HisGif?Stkcode=<#Stkcode>&Style=<#Style>&CodeIndex=<#CodeIndex>"></td>
<td><img src="<#ModuleName>/RealHQGif?Stkcode=<#Stkcode>&Style=<#Style>&CodeIndex=<#CodeIndex>&W=170&H=400&L=5"></td>
  </tr>
</table>
</div>
<script language="JavaScript1.2">setTimeout("SetString()",2000)  var content = '<table border="0" cellspacing="0" cellpadding="0">';
   content += '<tr>';
content += '<td><img id="Img" onMouseMove="ImgMove();" onMouseOut="ImgOut();" src="<#ModuleName>/HisGif?Stkcode=<#Stkcode>&Style=<#Style>&CodeIndex=<#CodeIndex>"></td>';
content += '<td><img src="<#ModuleName>/RealHQGif?Stkcode=<#Stkcode>&Style=<#Style>&CodeIndex=<#CodeIndex>&W=170&H=400&L=5"></td>';
   content += '</tr>';
content += '</table>';
function SetString()
{ 
document.getElementById("test").innerHTML=content;
}</script>
</body>
</html>setTimeout("SetString()",20000) 用这个来间隔20秒钟刷新的怎么就刷新第一次?