<a href="javascript:;" class="xq-sms">发送短信</a>

$(document).ready(function(){
    var u = navigator.userAgent;
    var isAndroid = u.indexOf('Android') > -1 || u.indexOf('Linux') > -1;
    var isIos = !!u.match(/\(i[^;]+;( U;)? CPU.+Mac OS X/);
    var current_url = window.location.href;
    if(isAndroid == true){
        $(".xq-sms").attr("href","sms:?body="+current_url);
    }
    else if(isIos == true){
        $(".xq-sms").attr("href","sms:&body="+current_url);
    }
});