//清楚網(wǎng)頁中所有文本框的內(nèi)容和下拉框
 function clearText()
{
    //清除文本框
   var col = Form1.getElementsByTagName("INPUT");
      for ( var i = 0;i < col.length;i ++ )
       {
              if ( col[i].type == "text" )
              col[i].value = ""; 
        }
     //清楚下拉框
     var selectlist=document.getElementsByTagName("select"); 
      for(var i=0;i < selectlist.length;i++)
          {
            selectlist[i].selectedIndex=0 ;
          }                                       
 }

//按回車觸發(fā)按鈕事件
<script language="javascript">
function document.onkeydown()
{
var e=event.srcElement;
if(event.keyCode==13)
{
document.getElementById("需要點(diǎn)擊的那個(gè)按鈕的id").click();
return false;
}
}
</script>