<html>
<body>
<script>
function selectGama1(){
//var choice = document.glink1.selectedIndex;
var choice = document.getElementById("glink1").selectedIndex;
alert(choice);
return choice;
}
</script>
<select class="Glink1" id="glink1" size=1>
<option selected value="0" > Г1 </option>
<option value="1" > Г13 </option>
<option value="2" > Г20 </option>
<option value="3" > Г23 </option>
</select>
<input type="button" value="Зашифровать" class="B1" onClick="selectGama1()">
</body>
</html>