html:
<input placeholder="搜索" id="toSearch" name="tosearch">

<ul class="bg-grey search-hide">
<li onclick="goSearch(S)">学生</li>
<li onclick="goSearch(A)">老师</li>
<li onclick="goSearch(M)">教授</li>
<li onclick="goSearch(C)">专家</li>
</ul>
JS:
function goSearch(searched){
var searchText = byId("toSearch").value;
switch(searched){
case S:
v = ss;
break;
case A:
v = aa;
break;
case M:
v = mm;
break;
case C:
v = cc;
break;
}

要求：当输入框中输入后，点击对应的获取相应的搜索内容来。报错：ReferenceError: S is not defined