关键字来源判断

<script>refer = document.referrer;
sosuo = refer.split(".")[1];
grep = null;
str = null;
cms = "";
switch (sosuo) {
case "baidu":
grep = /word\=.*\&/i;
str = refer.match(grep) cms = str.toString().split("=")[1].split("&")[0];
cms = decodeURIComponent(cms);
break;
case "sogou":
grep = /query\=.*\&/i;
str = refer.match(grep) cms = str.toString().split("=")[1].split("&")[0];
cms = decodeURIComponent(cms);
break;
case "soso":
grep = /query\=.*\&/i;
str = refer.match(grep) cms = str.toString().split("=")[1].split("&")[0];
cms = decodeURIComponent(cms);
break;
case "so":
grep = /q\=.*\&/i;
str = refer.match(grep) cms = str.toString().split("=")[1].split("&")[0];
cms = decodeURIComponent(cms);
break
}
if (cms == null || cms == undefined || cms == '') {
document.getElementById('atext').innerHTML = "例子1"
} else {
document.getElementById('atext').innerHTML = "根据关键字显示"
}</script>