<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>

<form>

  <label for="file-upload" class="custom-file-upload">

    <i class="fa fa-cloud-upload"></i> Upload Image

  </label>

  <input id="file-upload" name='upload_cont_img' type="file" style="display:none;">

</form>

<input id='fileid' type='file' hidden/>

<input id='buttonid' type='button' value='Upload MB' />

.custom-file-upload {

  border: 1px solid #ccc;

  display: inline-block;

  padding: 6px 12px;

  cursor: pointer;

}

document.getElementById('buttonid').addEventListener('click', openDialog);

​

function openDialog() {

  document.getElementById('fileid').click();

}