改变input file样式

You can't modify much about 

input[type=file]

.

Best you can do is place whatever you want to trigger it on your page, and then absolutely position the

input

 over
that with 

opacity:
0

.

The user's click on your apparent control will really trigger the invisible 

input

 on
top.

Here is how I may do it with CSS...

HTML

<div id="upload-file-container">
<input type="file" name="photo" />
</div>

CSS

#upload-file-container {
background: url(images/custom-file-input.png) no-repeat;
}

#upload-file-container input {
filter: alpha(opacity=0);
opacity: 0;
}