function menu(form)
{
 if((form.url.selectedIndex != 0)&&(form.url.selectedIndex != 1))
 self.location = form.url.options[form.url.selectedIndex].value 
}

document.write('<form name="withus" method="get">');
document.write('<select name="url" onchange="menu(this.form)">');
document.write('<option>ºÐ¾ç¾÷ü¹Ù·Î°¡±â</option>');
document.write('<option>================</option>');
document.write('<option value="/company/ssidi/">(ÁÖ)»ï¼ºIDI</option>');
document.write('<option value="/company/company_model/">ºÐ¾ç¾÷ü¸ðÁýÁß</option>');
document.write('</select></form>');