jquery ajax 异步数据交换

function addTopKeyWords(){
// alert(num);
var topWords = $('#topWordsInput').val();
if(topWords ==""){
$.messager.alert('系统警告',mess.topWords,'warning');
return false;
}else{
$.ajax({
async: true,
type: "POST",
url: "${basePath}secure/AddTopKeyWords.action?topWords="+encodeURIComponent(topWords)+"&columnId=${columnId}",
success: function(data){
// alert(data);
var mess = eval('('+data+')');
$('#showTopWords').html(mess.topWords);
}
});
return false;
}
}