问cursor:pointer属性不适用于Webkit浏览器中的文件上载按钮

EN

.file-wrapper {
    cursor: pointer;
    display: inline-block;
    overflow: hidden;
    position: relative;
}
.file-wrapper input {
    cursor: pointer;
    font-size: 100px;
    height: 100%;
    filter: alpha(opacity=1);
    -moz-opacity: 0.01;
    opacity: 0.01;
    position: absolute;
    right: 0;
    top: 0;
}
.file-wrapper .button {
    background: #79130e;
    -moz-border-radius: 5px;
    -webkit-border-radius: 5px;
    border-radius: 5px;
    color: #fff;
    cursor: pointer;
    display: inline-block;
    font-size: 11px;
    font-weight: bold;
    margin-right: 5px;
    padding: 4px 18px;
    text-transform: uppercase;
}

<span class="file-wrapper">
   <input type="file" name="photo" id="photo" />
   <span class="button">Choose a Photo</span>
</span>