So you want to get the value of the selected option onchange of option value right? You can try this way:-
http://jsfiddle.net/T8CKU/
<select name="p1" onchange="myfunc(this.value);">
<option value="A">A</option>
<option value="B">B</option>
<option value="C">C</option>
</select>
function myFunc(menuValue){
alert(menuValue)
}
Here inside myFunc the context of `this would be the window. If you want to get the context inside the window as the dropdown itself you can use apply or call.
<select name="p1" onchange="myFunc.call(this);">
<option value="A">A</option>
<option value="B">B</option>
<option value="C">C</option>
</select>
function myFunc(){
alert(this.value); //This will give the value again.
}