function tz_calculate(timestamp){var d=new Date();var raw_offset=d.getTimezoneOffset()/30;var time_sec=d.getTime()/1000;var time_diff=Math.round((timestamp-time_sec)/1800);var rounded_offset=Math.round(raw_offset+time_diff)%48;if(rounded_offset==0){return 0;}else if(rounded_offset>24){rounded_offset-=Math.ceil(rounded_offset/48)*48;}else if(rounded_offset<-28){rounded_offset+=Math.ceil(rounded_offset/-48)*48;}
return rounded_offset*30;}
function ajax_tz_set(tzForm){var timestamp=tzForm.time.value;var gmt_off=-tz_calculate(timestamp);var cur_gmt_off=tzForm.tz_gmt_off.value;if(gmt_off!=cur_gmt_off){var ajaxUrl='ajax/autoset_timezone_ajax.php';var ajax=new Ajax();params='user='+tzForm.user.value
+'&post_form_id='+tzForm.post_form_id.value
+'&gmt_off='+gmt_off;ajax.post(ajaxUrl,params);}}
function tz_autoset(){var tz_form=ge('tz_autoset_form');if(tz_form)
ajax_tz_set(tz_form);}