使用CSS和JavaScript的自定义上传按钮

Question

I'm trying to code a custom upload button. I've hidden the regular one and then put a div with image background over the top.

It works great but I want to fill the (disabled) input field below with the file name once the user selects a file but it's not working.

JavaScript:

document.getElementById("upload_button").onchange = function () {
document.getElementById("upload_file").value = this.value;
};

HTML:

<div id="Form_FileInput_Container"><input type="file" id="upload_button" /></div>
<input class="Form_Input" id="upload_file" placeholder="Choose File" disabled="disabled" />

CSS:

#Form_FileInput_Container { position: relative; width: 100px; height: 100px; background: #e5e5e5 url('path/to/upload/image/forms_upload.png') no-repeat; border: 1px solid #cccccc; }
#Form_FileInput_Container input { filter: alpha(opacity=0); opacity: 0; width: 100px; height: 100px; }

Any help is most appreciated :)

Answer 1

Make sure you attach your JavaScript after the elements exist.

<input id="foo" type="file" />
<input id="bar" type="text" placeholder="Choose File" disabled />

// after elements exist
var foo = document.getElementById('foo'),
    bar = document.getElementById('bar');

foo.addEventListener('change', function () {
    var slash = this.value.lastIndexOf('\\');
    bar.value = this.value.slice(slash + 1);
});

DEMO

Answer 2

HTML:

<input type="file" id="upload_button" onchange="cutomButton()" /> 

JS:

function customButton() {
    var z=document.getElementById("upload_button").value;
    document.getElementById("upload_file").value = z;
    alert(document.getElementById("upload_file").value);
}