Fix `firefox` upload folder prompt window

dist/example.js

@@ -1398,20 +1398,19 @@
 	      if (!this.$refs.upload.features.directory) {
 	        return;
 	      }
-	      this.$refs.upload.$el.onclick = null;
 	
+	      var input = this.$refs.upload.$el.querySelector('input');
+	      input.directory = true;
+	      input.webkitdirectory = true;
 	      this.directory = true;
-	      this.$nextTick(function () {
-	        _this.$refs.upload.$el.querySelector('input').click();
-	        _this.$refs.upload.$el.onclick = function (e) {
-	          e.preventDefault();
-	          _this.directory = false;
-	          _this.$refs.upload.$el.onclick = null;
-	          _this.$nextTick(function () {
-	            _this.$refs.upload.$el.querySelector('input').click();
-	          });
-	        };
-	      });
+	
+	      input.onclick = null;
+	      input.click();
+	      input.onclick = function (e) {
+	        _this.directory = false;
+	        input.directory = false;
+	        input.webkitdirectory = false;
+	      };
 	    },
 	    inputFilter: function inputFilter(newFile, oldFile, prevent) {
 	      if (newFile && !oldFile) {
@@ -3950,7 +3949,7 @@
 	      "headers": _vm.headers,
 	      "data": _vm.data,
 	      "drop": _vm.drop,
-	      "dropDirectory": _vm.dropDirectory
+	      "drop-directory": _vm.dropDirectory
 	    },
 	    on: {
 	      "input-filter": _vm.inputFilter,

example/Home.vue

@@ -241,20 +241,19 @@ export default {
       if (!this.$refs.upload.features.directory) {
         return
       }
-      this.$refs.upload.$el.onclick = null
 
+      let input = this.$refs.upload.$el.querySelector('input')
+      input.directory = true
+      input.webkitdirectory = true
       this.directory = true
-      this.$nextTick(() => {
-        this.$refs.upload.$el.querySelector('input').click()
-        this.$refs.upload.$el.onclick = (e) => {
-          e.preventDefault()
-          this.directory = false
-          this.$refs.upload.$el.onclick = null
-          this.$nextTick(() => {
-            this.$refs.upload.$el.querySelector('input').click()
-          })
-        }
-      })
+
+      input.onclick = null
+      input.click()
+      input.onclick = (e) => {
+        this.directory = false
+        input.directory = false
+        input.webkitdirectory = false
+      }
     },