update web-view.uvue 补充平台条件判断

pages/component/web-view/web-view.uvue

@@ -122,8 +122,14 @@
       },
       load(event : UniWebViewLoadEvent) {
         console.log(JSON.stringify(event.detail));
+        // #ifdef APP
         this.canGoBack = canWebViewGoBack('web-view');
         this.canGoForward = canWebViewGoForward('web-view');
+        // #endif
+        // #ifdef WEB
+        this.canGoBack = canWebViewGoBack(this.webviewElement as UniWebViewElement);
+        this.canGoForward = canWebViewGoForward(this.webviewElement as UniWebViewElement);
+        // #endif
         if (this.autoTest) {
           this.eventLoad = {
             "tagName": event.target?.tagName,