function showtab(a) { var mainChildren = document.querySelector(".mainpadd").children; if(a==1) { for (i=1; i<mainChildren.length; i++) { mainChildren[i].style.display="none"; } document.getElementById("container2").style.display="block"; document.getElementById("container3").style.display="none";} else if(a==2) { for (i=1; i<mainChildren.length; i++) {mainChildren[i].style.display="block";}document.getElementById("container2").style.display="none"; document.getElementById("container3").style.display="none";} else {for (i=1; i<mainChildren.length; i++) { mainChildren[i].style.display="none"; } document.getElementById("container2").style.display="none"; document.getElementById("container3").style.display="block";}}document.getElementById("necessary_tab").innerHTML='<li class="nownav" id="tab3" onmouseover="showtab(3)" style="border-right: 1px solid; padding-right: 16px;"><h2>相关推荐</h2></li><li class="nownav" id="tab1" onmouseover="showtab(2)"><h2>推搡三国历史版本</h2></li>';showtab(3);