Cross-browser custom styling for file upload button

I'm posting this because (to my surprise) there was no other place I could find that recommended this.

There's a really easy way to do this, without restricting you to browser-defined input dimensions. Just use the <label> tag around a hidden file upload button. This allows for even more freedom in styling than the styling allowed via webkit's built-in styling^[1].

The label tag was made for the exact purpose of directing any click events on it to the child inputs^[2], so using that, you won't require any JavaScript to direct the click event to the input button for you anymore. You'd to use something like the following:

label.myLabel input[type="file"] {
    position:absolute;
    top: -1000px;
}

/***** Example custom styling *****/
.myLabel {
    border: 2px solid #AAA;
    border-radius: 4px;
    padding: 2px 5px;
    margin: 2px;
    background: #DDD;
    display: inline-block;
}
.myLabel:hover {
    background: #CCC;
}
.myLabel:active {
    background: #CCF;
}
.myLabel :invalid + span {
    color: #A44;
}
.myLabel :valid + span {
    color: #4A4;
}

<label class="myLabel">
    <input type="file" required/>
    <span>My Label</span>
</label>

I've used a fixed position to hide the input, to make it work even in ancient versions of Internet Explorer (emulated IE8- refused to work on a visibility:hidden or display:none file-input). I've tested in emulated IE7 and up, and it worked perfectly.

1. You can't use <button>s inside <label> tags unfortunately, so you'll have to define the styles for the buttons yourself. To me, this is the only downside to this approach.
2. If the for attribute is defined, its value is used to trigger the input with the same id as the for attribute on the <label>.

Please find below a way that works on all browsers. Basically I put the input on top the image. I make it huge using font-size so the user is always clicking the upload button.

.myFile {
  position: relative;
  overflow: hidden;
  float: left;
  clear: left;
}
.myFile input[type="file"] {
  display: block;
  position: absolute;
  top: 0;
  right: 0;
  opacity: 0;
  font-size: 100px;
  filter: alpha(opacity=0);
  cursor: pointer;
}

<label class="myFile">
  <img src="http://wscont1.apps.microsoft.com/winstore/1x/c37a9d99-6698-4339-acf3-c01daa75fb65/Icon.13385.png" alt="" />
  <input type="file" />
</label>

The best example is this one, No hiding, No jQuery, It's completely pure CSS

http://css-tricks.com/snippets/css/custom-file-input-styling-webkitblink/

.custom-file-input::-webkit-file-upload-button {
    visibility: hidden;
}

.custom-file-input::before {
    content: 'Select some files';
    display: inline-block;
    background: -webkit-linear-gradient(top, #f9f9f9, #e3e3e3);
    border: 1px solid #999;
    border-radius: 3px;
    padding: 5px 8px;
    outline: none;
    white-space: nowrap;
    -webkit-user-select: none;
    cursor: pointer;
    text-shadow: 1px 1px #fff;
    font-weight: 700;
    font-size: 10pt;
}

.custom-file-input:hover::before {
    border-color: black;
}

.custom-file-input:active::before {
    background: -webkit-linear-gradient(top, #e3e3e3, #f9f9f9);
}

<input type="file" class="custom-file-input">

This seems to take care of business pretty well. A fidde is here:

HTML

<label for="upload-file">A proper input label</label>

<div class="upload-button">

    <div class="upload-cover">
         Upload text or whatevers
    </div>

    <!-- this is later in the source so it'll be "on top" -->
    <input name="upload-file" type="file" />

</div> <!-- .upload-button -->

CSS

/* first things first - get your box-model straight*/
*, *:before, *:after {
    -moz-box-sizing: border-box;
    -webkit-box-sizing: border-box;
    box-sizing: border-box;
}

label {
    /* just positioning */
    float: left; 
    margin-bottom: .5em;
}

.upload-button {
    /* key */
    position: relative;
    overflow: hidden;

    /* just positioning */
    float: left; 
    clear: left;
}

.upload-cover { 
    /* basically just style this however you want - the overlaying file upload should spread out and fill whatever you turn this into */
    background-color: gray;
    text-align: center;
    padding: .5em 1em;
    border-radius: 2em;
    border: 5px solid rgba(0,0,0,.1);

    cursor: pointer;
}

.upload-button input[type="file"] {
    display: block;
    position: absolute;
    top: 0; left: 0;
    margin-left: -75px; /* gets that button with no-pointer-cursor off to the left and out of the way */
    width: 200%; /* over compensates for the above - I would use calc or sass math if not here*/
    height: 100%;
    opacity: .2; /* left this here so you could see. Make it 0 */
    cursor: pointer;
    border: 1px solid red;
}

.upload-button:hover .upload-cover {
    background-color: #f06;
}