[krol]

Объясните пожалуйста почему не выполняется 3-е условие?

<script type="text/javascript">

function show() {
var visible = true;
if(document.my.menu.value==2 || document.my.menu.value==4 || document.my.menu.value==5) {
        document.getElementById('size1' ).style.display = 'none';
        visible = false;
    } else {
        document.getElementById('size1' ).style.display = 'block';
        visible = true;
    }

 if(document.my.menu.value==1) {
        document.getElementById('size2' ).style.display = 'none';
        visible = false;
    } else {
        document.getElementById('size2' ).style.display = 'block';
        visible = true;
    }
	 
if(document.my.menu.value==3) {
        document.getElementById('size3' ).style.display = 'none';
        visible = false;
    } else {
        document.getElementById('size3' ).style.display = 'block';
        visible = true;
    }

}
</script>



<form action="" method="get" name="my">
  <select name="menu"  onChange="show()">
      <option value="1">1</option>
      <option value="2">2</option>
      <option value="3">3</option>
      <option value="4">4</option>
      <option value="5">5</option>
      
  </select>
</form>
<div id="size1" style="display:none;">1</div>
<div id="size2" style="display:none;">2</div>
<div id="size3" style="display:none;">3</div>