function formHandler(){
var URL = document.form.site.options[document.form.site.selectedIndex].value;
window.location.href = URL;
}

document.write('<form name="form">');
document.write('<select name="site" class=menubox size=1 onChange="javascript:formHandler()">');
document.write('<option value="index.htm">...Menu...');
document.write('<option value="javascript:history.go(-1);">...Previous Page...');
document.write('<option value="http://www.owensound.ca/business/enterprisecentre">Business Enterprise Centre');
document.write('<option value="eastside.htm">East Side');
document.write('<option value="westside.htm">West Side');
document.write('<option value="downtown.htm">Downtown');
document.write('<option value="needs-study.htm">Commercial Needs Study');
document.write('<option value="index.htm">Intro');
document.write('</select>');
document.write('</form>');