JS实现alert中显示换行的方法

//浏览器类型判定function getOs(){ ?if(navigator.userAgent.indexOf("MSIE")>0) { ????return "IE"; //InternetExplor ?} ?else if(isFirefox=navigator.userAgent.indexOf("Firefox")>0){ ????return "FF"; //firefox ?} ?else if(isSafari=navigator.userAgent.indexOf("Safari")>0) { ????return "SF"; //Safari ?} ?else if(isCamino=navigator.userAgent.indexOf("Camino")>0){ ????return "C"; //Camino ?} ?else if(isMozilla=navigator.userAgent.indexOf("Gecko/")>0){ ????return "G"; //Gecko ?} ?else if(isMozilla=navigator.userAgent.indexOf("Opera")>=0){ ????return "O"; //opera ?}else{ ???return ‘Other‘; ?}}function alert_br(){ ?var os=getOs(); ?if(os==‘FF‘ || os==‘SF‘){ //FireFox、谷歌浏览器用这个 ???alert(‘第一行\n第二行‘); ?}else{ ?//IE系列用这个 ???alert(‘第一行\r\n第二行‘); ?}}alert_br();