dima_riabets,
<!DOCTYPE HTML>
<html>
<head>
<title>Untitled</title>
<meta charset="utf-8">
</head>
<body>
<input type="text" size="35" style="width:100%;" name="title" value="" maxlength="200" >
<select size="1" id="sfF18" class="manFlSel" name="filter1">
<option value="0" style="color:#A3A3A3">- выбрать -</option>
<option value="11">A</option><option value="12">B</option>
<option value="13">C</option><option value="14">D</option>
<option value="15">E</option><option value="16">F</option>
<option value="17">G</option><option value="18">H</option>
<option value="19">I</option><option value="20">J</option>
<option value="21">K</option><option value="22">M</option>
<option value="23">N</option><option value="24">O</option>
<option value="25">P</option><option value="26">Q</option>
<option value="27">R</option><option value="28">S</option>
<option value="29">T</option><option value="30">Q</option>
<option value="31">V</option><option value="32">W</option>
<option value="33">X</option><option value="34">Y</option>
<option value="35">Z</option>
</select>
<script>
var sel = document.querySelector('#sfF18'),
opts = Array.apply(null, sel.options),
map = {};
opts.forEach(function (el) {
map[el.text] = el.value
})
document.querySelector('[name="title"]').oninput = function () {
sel.value = map[this.value.charAt(0).toLocaleUpperCase()] || 0
}
</script>
</body>
</html>