Frames and Javascript Question

I have two frames one is called leftFrame and it has a drop down box. When the value in the drop down box changes I want it to display the link in the other frame which is called mainFrame. This is the code I tried to use but it wouldn't work. Can someone PLEASE HELP!!

<form style="margin-top:0pt">
<select onChange="javascript: window.mainFrame.href=this.options[this.selectedIndex].value;">

<option value="#" selected>Choose one</option>
<option value="/health/producer/newsletter/jun04.htm">June, 2004</option>
<option value="/health/producer/newsletter/may04.htm">May, 2004</option>
<option value="/health/producer/newsletter/apr04.htm">April, 2004</option>
<option value="/health/producer/newsletter/mar04.htm">March, 2004</option>
<option value="/health/producer/newsletter/feb04.htm">February, 2004</option>
<option value="/health/producer/newsletter/jan04.htm">January, 2004</option>
<option value="/health/producer/newsletter/dec2003/index.htm">December, 2003</option>
<option value="/health/producer/newsletter/nov03.htm">November, 2003</option>
<option value="/health/producer/newsletter/oct03.htm">October, 2003</option>
<option value="/health/producer/newsletter/sep03.htm">September, 2003</option>
<option value="/health/producer/newsletter/aug03.htm">August, 2003</option>
<option value="/health/producer/newsletter/jun03.htm">June, 2003</option>
<option value="/health/producer/newsletter/may03.htm">May, 2003</option>
</select>
</form>

just a couple of syntax errors in the onChange code...try this

<select onChange="parent.mainFrame.location.href=this.options[this.selectedIndex].value;">

When dealing with frames you have to reference the parent in order to get access to the frames

Thanks