function librarySearch(){

var chkbox=document.getElementsByName("tag_tmp");
var str="";

for(var i=0;i<chkbox.length;i++){
 if (chkbox[i].checked){
  str+=" AND "+chkbox[i].value;
 }
}
 str = str.replace(" AND ", "");
 document.getElementById("tag").value=str;

 return false;
}