function select_tn(showContent,selfObj){
// ±êÇ©
var tag = document.getElementById("tags").getElementsByTagName("li");
var taglength = tag.length;
for(i=0; i<taglength; i++){
tag[i].className = "";
}
selfObj.parentNode.className = "tn_net";
// ±êÇ©ÄÚÈÝ
for(i=0; j=document.getElementById("tabnnet"+i); i++){
j.style.display = "none";
}
document.getElementById(showContent).style.display = "block";
}