function secBoard(obj,n)
{
	
    for(i=0;i<mainTableA.tBodies.length;i++){
	 //先隐藏所有table
	
      mainTableA.tBodies[i].style.display="none";
	}
	//然后显示指定的table
     mainTableA.tBodies[n].style.display="block";

    for(i=0;i<imgarea.length;i++){
		imgarea[i].src="../images/tz"+i+".gif";
	}
	imgarea[n].src="../images/tz"+n+"_"+n+".gif";
	
	if(n==0){
		document.all.handlemore.innerHTML = '<a href ="../tzgg_226/" >更多&gt;&gt;</a>';
	}
	if(n==1){
		document.all.handlemore.innerHTML = '<a href ="../bmxx_227/" >更多&gt;&gt;</a>';
	}
}