Edit in JSFiddle

document.getElementById("uploadBtn").onchange = function () {
    document.getElementById("uploadFile").value = this.value;
};

<input id="uploadFile" placeholder="Choose File" readonly />
<div class="fileUpload btn btn-primary">
    <span>Upload</span>
    <input id="uploadBtn" type="file" class="upload" />
</div>

.fileUpload {
	position: relative;
	overflow: hidden;
	margin: 10px;
}
.fileUpload input.upload {
	position: absolute;
	top: 0;
	right: 0;
	margin: 0;
	padding: 0;
	font-size: 20px;
	cursor: pointer;
	opacity: 0;
	filter: alpha(opacity=0);
}