!139 update docs/component/picker.md.

* update docs/component/picker.md.

docs/component/picker.md

@@ -198,7 +198,7 @@ export default {
     },
     methods: {
         bindPickerChange: function(e) {
-            console.log('picker发送选择改变，携带值为', e.target.value)
+            console.log('picker发送选择改变，携带值为', e.detail.value)
             this.index = e.target.value
         },
         bindDateChange: function(e) {