<select name="type" onchange="nones();return false;" id="type" class="inp_s" style="width: 100%;font-size: 18px;">
	<option value="Advertise">Advertise</option>
	<option value="Link">Link</option>
	</select>

<input type="number" name="impr" min="0" value="0" placeholder="Impressions" id="impressions" class="inp_s">

<script>
function nones() {
    if (document.getElementById("type") == "Link") {
        document.getElementById("impressions").style.display = "none";
    }
}
</script>