U.Helper

$('input[name="other1"]').hide().parent().html('<select id="filter1select" name="filter1select" onchange=""><option value="0"></option><option value="1">49</option><option value="2">70-110</option><option value="3">125-150</option><option value="4">160-300</option><option value="5">350-500</option><option value="6">600-800</option></select>');
$('#filter1select').change(function() {
$('input[name="other1"]').val($(this).val());
});

<input name="other1" value="Тест" />

<script>
$('input[name="other1"]').before('<select id="filter1select" name="filter1select" onchange=""><option value="0"></option><option value="49">49</option><option value="70-110">70-110</option><option value="125-150">125-150</option><option value="160-300">160-300</option><option value="350-500">350-500</option><option value="600-800">600-800</option></select>');
$('#filter1select').change(function() {
$('input[name="other1"]').val($(this).val());
});
</script>

<input name="other1" value="5" />
   
<script>
$('input[name="other1"]').hide(0).before('<select id="filter1select" name="filter1select" onchange=""><option value="5">5</option><option value="49">49</option><option value="70-110">70-110</option><option value="125-150">125-150</option><option value="160-300">160-300</option><option value="350-500">350-500</option><option value="600-800">600-800</option></select>');
$('#filter1select').change(function() {
$('input[name="other1"]').val($(this).val());
});
</script>

<script language="javascript" type="text/javascript">
$('input[name="other1"]').hide().before('<select id="sel" name="fl"><option value="5">5</option><option value="49">49</option><option value="70-110">70-110</option><option value="125-150">125-150</option><option value="160-300">160-300</option><option value="350-500">350-500</option><option value="600-800">600-800</option></select>');

<?if($PAGE_ID$='edit')?>
$(function () {
var fsell = $('input[name="other1"]').val();
if(fsell != '') { $('#sel').val(fsell)}
})
<?endif?>
</script>