Passing select boxes as parameter so only using one function

Question

Hello to all. I"m having trouble with my Javascript. I tried posting this question to some "Javascript" forums and nobody has replied until now I guess they don't know the answer, so I'm hoping that you guys here can answer this kind of question.
Here was my post
"Hello. Is there any way that I can pass an actual <select> box as a parameter so I can use only one function in my javascript. Hmm.. here's kind of the situation
I have two select boxes
selectbox1 and selectbox2
and for each select box I have a javascript function
myfunction1 and myfunction2
these functions do exactly the same thing
how can I do it in such a way that it accepts the select box as a parameter and how do I use that parameter when inside the function?"

Answer 1

You can use the keyword "this" to pass a reference to the <select> box as a parameter to the function.
In the case of events "this" refers to the object the event is being invoked on - button, selectbox, textfield...
<script language="javascript">
  function changeCombo(theSelectBox){
    alert('you changed ' + theSelectBox.name);
    alert("value = " + theSelectBox.value);
</script>
<hr>
Letter: <select name="s1" onchange="changeCombo(this)">
  <option value="a">a
  <option value="b">b
  <option value="c">c
</select>
Number: <select name="s2" onchange="changeCombo(this)">
  <option value="1">1
  <option value="2">2
  <option value="3">3
</select>