document.getElementById('span_class').innerHTML = "<form id=\"speed\" name=\"speed\" action=\"\"><select name=\"big_class_id\" onchange=\"javascript:if(this.options[selectedIndex].value==0){window.location.href=\'/\'}else{window.location.href=\'/\'+this.options[selectedIndex].url_prefix+\'/dir_\'+this.options[selectedIndex].value+\'.html\'}\"><option value=\'\'>产品中心快速通道</option><option value=\"3\" url_prefix=\"mobile\" >手机通讯</option><option value=\"7\" url_prefix=\"pc\" >本本整机</option><option value=\"1\" url_prefix=\"digital\" >数码产品</option><option value=\"8\" url_prefix=\"diy\" >DIY配件</option><option value=\"2\" url_prefix=\"digi_accessories\" >数码配件</option><option value=\"14\" url_prefix=\"digi_home\" >数字家电</option><option value=\"9\" url_prefix=\"network\" >网络设备</option><option value=\"12\" url_prefix=\"additional\" >扩展配件</option><option value=\"11\" url_prefix=\"office\" >外设办公</option><option value=\"13\" url_prefix=\"supplies\" >耗材相关</option><option value=\"16\" url_prefix=\"household_appliances\" >小家电</option><option value=\"17\" url_prefix=\"kitchen_appliances\" >厨卫家电</option><option value=\"15\" url_prefix=\"software\" >软件产品</option></select></form>";