使用 CSS 去掉 iPhone 网页上按钮的超大圆角默认样式
使用 iPhone 上的浏览器去浏览网页的时候，按钮总是显示超大圆角的样式，显得超级恶心，但是我们自己定义 border-radius 为 0 也无法去除这个圆角，经过搜索发现这是 webikt 内核浏览器通过私有属性 -webkit-appearance 对控件设置了默认样式。
我们只要对按钮设置这个属性，并设置为 'none' 就可以取消浏览器对于控件的默认样式。
input {-webkit-appearance:none; /*去除input默认样式*/}另外这个属性也有个神奇的地方，它可以用来调用显示浏览器对各种控件的默认样式，总共有如下几个效果（将一个 Span 标签应用不同的 -webkit-appearance 效果）：
| -webkit-appearance | 效果 |
|---|---|
| -webkit-appearance: button | SPAN Tag |
| -webkit-appearance: button-bevel | SPAN Tag |
| -webkit-appearance: caret | SPAN Tag |
| -webkit-appearance: checkbox | SPAN Tag |
| -webkit-appearance: listbox | SPAN Tag |
| -webkit-appearance: listitem | SPAN Tag |
| -webkit-appearance: menulist | SPAN Tag |
| -webkit-appearance: menulist-button | SPAN Tag |
| -webkit-appearance: menulist-text | SPAN Tag |
| -webkit-appearance: menulist-textfield | SPAN Tag |
| -webkit-appearance: push-button | SPAN Tag |
| -webkit-appearance: radio | SPAN Tag |
| -webkit-appearance: scrollbarbutton-down | SPAN Tag |
| -webkit-appearance: scrollbarbutton-left | SPAN Tag |
| -webkit-appearance: scrollbarbutton-right | SPAN Tag |
| -webkit-appearance: scrollbarbutton-up | SPAN Tag |
| -webkit-appearance: scrollbargripper-horizontal | SPAN Tag |
| -webkit-appearance: scrollbargripper-vertical | SPAN Tag |
| -webkit-appearance: scrollbarthumb-horizontal | SPAN Tag |
| -webkit-appearance: scrollbarthumb-vertical | SPAN Tag |
| -webkit-appearance: scrollbartrack-horizontal | SPAN Tag |
| -webkit-appearance: scrollbartrack-vertical | SPAN Tag |
| -webkit-appearance: searchfield | SPAN Tag |
| -webkit-appearance: searchfield-cancel-button | SPAN Tag |
| -webkit-appearance: searchfield-decoration | SPAN Tag |
| -webkit-appearance: searchfield-results-button | SPAN Tag |
| -webkit-appearance: searchfield-results-decoration | SPAN Tag |
| -webkit-appearance: slider-horizontal | SPAN Tag |
| -webkit-appearance: slider-vertical | SPAN Tag |
| -webkit-appearance: sliderthumb-horizontal | SPAN Tag |
| -webkit-appearance: sliderthumb-vertical | SPAN Tag |
| -webkit-appearance: square-button | SPAN Tag |
| -webkit-appearance: textarea | SPAN Tag |
| -webkit-appearance: textfield | SPAN Tag |
