如何用JavaScript编写长尾词来模拟ping判断IP地址是否连通？

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javascriptfunction ping(ip, callback) { if (!/^(\d{1,3}\.){3}\d{1,3}$/.test(ip)) { if (callback && callback.error) { callback.error(); } return; } var img=new Image(); var start=new Date().getTime(); img.onload=function() { var duration=new Date().getTime() - start; callback(null, duration); }; img.onerror=function() { callback(new Error('Ping failed'), null); }; img.src='http://' + ip + '/?t=' + start;}

ping

function ping(ip,callback){ if(!/^((2[0-4]\d|25[0-5]|[01]?\d\d?)\.){3}(2[0-4]\d|25[0-5]|[01]?\d\d?)$/.test(ip)){ if(callback&&callback.error){ callback.error(); } return; } var img = new Image(); var start = new Date().getTime(); var flag = false; var isCloseWifi = false; var hasFinish = false; img.onload = function() { if ( !hasFinish ) { flag = true; hasFinish = true; if(callback&&callback.success){ callback.success(); } } }; img.onerror = function() { if ( !hasFinish ) { if ( !isCloseWifi ) { flag = true; if(callback&&callback.success){ callback.success(); } } else { if(callback&&callback.error){ callback.error(); } } hasFinish = true; } }; img.src = '' + ip + '/' + start; setTimeout(function() { if ( !flag ) { hasFinish = true; flag = false ; if(callback&&callback.error){ callback.error(); } } }, 50); };