css - Twitter Bootstrap Form File Element Upload Button

Question

Why isn't there a fancy file element upload button for twitter bootstrap? It would be sweet if the blue primary button was implemented for the upload button. Is it even possible to finesse the upload button using CSS? (seems like a native browser element that can't be manipulated)

Answer 1

Here's a solution for Bootstrap 3 and 4.

To make a functional file input control that looks like a button, you only need HTML:

HTML

<label class="btn btn-default">
    Browse <input type="file" hidden>
</label>

This works in all modern browsers, including IE9+. If you need support for old IE as well, please use the legacy approach shown below.

This techniques relies on the HTML5 hidden attribute. Bootstrap 4 uses the following CSS to shim this feature in unsupportive browsers. You may need to add if you're using Bootstrap 3.

[hidden] {
  display: none !important;
}

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Legacy approach for old IE

If you need support for IE8 and below, use the following HTML/CSS:

HTML

<span class="btn btn-default btn-file">
    Browse <input type="file">
</span>

CSS

.btn-file {
    position: relative;
    overflow: hidden;
}
.btn-file input[type=file] {
    position: absolute;
    top: 0;
    right: 0;
    min-width: 100%;
    min-height: 100%;
    font-size: 100px;
    text-align: right;
    filter: alpha(opacity=0);
    opacity: 0;
    outline: none;
    background: white;
    cursor: inherit;
    display: block;
}

Note that old IE doesn't trigger the file input when you click on a <label>, so the The CSS "bloat" does a couple things to work around that:

• Makes the file input span the full width/height of the surrounding <span>
• Makes the file input invisible

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Feedback & Additional Reading

I've posted more details about this method, as well as examples for how to show the user which/how many files are selected:

https://www.abeautifulsite.net/posts/whipping-file-inputs-into-shape-with-bootstrap-3/