[improvement] Search: add placeholder-style prop (#788)

packages/search/README.md

@@ -56,6 +56,8 @@ Search 支持自定义右侧取消按钮，使用名字为 action 的 slot 即
 | readonly | 是否只读 | `Boolean` | `false` |
 | maxlength | 最大输入长度，设置为 -1 的时候不限制最大长度 | `Number` | `-1` |
 | use-action-slot | 是否使用 action slot | `Boolean` | `false` |
+| placeholder | 输入框为空时占位符 | `String` | - |
+| placeholder-style | 指定 placeholder 的样式 | `String` | - |
 
 ### Event
 

packages/search/index.ts

@@ -12,6 +12,7 @@ VantComponent({
     showAction: Boolean,
     useActionSlot: Boolean,
     placeholder: String,
+    placeholderStyle: String,
     background: {
       type: String,
       value: '#f2f2f2'

packages/search/index.wxml

@@ -15,6 +15,7 @@
       readonly="{{ readony }}"
       maxlength="{{ maxlength }}"
       placeholder="{{ placeholder }}"
+      placeholder-style="{{ placeholderStyle }}"
       custom-style="padding: 3px 10px"
       bind:blur="onBlur"
       bind:focus="onFocus"