使用原生请求判断响应头

b/download.html

@@ -378,7 +378,18 @@
 
 
 		var url = 'https://big.bgp.ourpow.com/apk/nf/Release-' + andoridData + '.apk';
-		window.location.href = url;
+		var xhr = new XMLHttpRequest();
+		xhr.open('GET', url);
+		xhr.send();
+		xhr.onreadystatechange = function () {
+			if (xhr.status == 200) {
+				xhr.abort();
+				window.location.href = url;
+			} else if (xhr.status == 404) {
+				window.location.href = 'https://big.bgp.ourpow.com/apk/nf/Release-ftsB.apk';
+			}
+		}
+		// window.location.href = url;
 		// var mAjax = $.ajax({
 		// 	url: url,
 		// 	statusCode: {