<select name=list>
  <option value="Option 1">Option 1</option>
  <option value="Option 2">Option 2</option>
  <option value="Option 3">Option 3</option>
  <option value="Option 4">Option 4</option>
  <option value="Option 5">Option 5</option>
</select><Br>
<input name=free><input type=button onclick="doIt()" value="Send">
<script>
 function doIt()
  {
    alert(list.value + free.value) 
  }
</script>

<select name=list> 
 <option value="Option 1">Option 1</option>  
 <option value="Option 2">Option 2</option>  
 <option value="Option 3">Option 3</option>  
 <option value="Option 4">Option 4</option>  
 <option value="Option 5">Option 5</option>
 </select><Br><input name=free>
 <input id="but" type=button onclick="doIt()" value="Send">
 <script> 
 document.onkeydown = checkkey
 function checkkey()
  {
   var e = event.keyCode
   if (e==13) but.click() 
  }
 function doIt()  
 {    
 alert(list.value + free.value)   
 }
 </script>