Демьян,
Рабочий вариант ...
<!DOCTYPE html>
<html>
<head>
<title></title>
</head>
<body>
<form id="form" name="form">
<select name="spisok" id="spisok" style="width: 155px;"
onchange="if (this.value == '1' ) { document.getElementById('div').style.display = 'inline';
document.getElementById('pole').focus();}
else {document.getElementById('div').style.display = 'none'}">
<option selected="selected" value="0"></option>
<option value="1">1-я строка списка</option>
</select>
<div id="div" style="display:none;">
<input id="pole" type="text" style="width:30px;"/>
</div>
</form>
</body>
</html>