预产期计算

　　孕妇预产期计算器：整个孕期约为40周，即9个月零7天左右，通过末次月经时间可以推算预产期。推算方法是按末次月经时间的第一日算起，月份减3或加9，日数加7。但是实际分娩日期与推算的预产期可能会相差1～2周，如果孕妇的末次月经日期记忆不清或月经不准，就需要医生代为测算预产期。  提醒： 预产期的计算会使初为妈妈的你做到“心中有数”，虽然只有不到５％的孕妇会刚好在预产期那天分娩。

　　你末次月经的第一天是什么时候： 年 月 日

　　你的月经周期是 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 天

　　您的预产期是：

　　您现在正处于孕期的第 周var health=document.getElementById("health");function healthtime(){var heihei = new Date();var countyear = heihei.getFullYear();var countmonth = heihei.getMonth();var countday = heihei.getDate();document.health.year.value = countyear;document.health.month.value = countmonth+1;document.health.day.value = countday;}function haha(){if (health.year.value=="" || health.month.value=="" || health.day.value ==""){alert("请填写完整年月日!");return false;}if (health.year.value>2050 || health.year.value<1990){alert("请填写正确年份!");health.year.focus();return false;}if (health.month.value>12 || health.month.value<1){alert("请填写正确月份!");health.month.focus();return false;}if (health.day.value>31 || health.day.value<1){alert("请填写正确日子!");health.day.focus();return false;}if (!isDate(health.year.value ,health.month.value ,health.day.value)){alert("年月日组合有错,请重新填写!");return false;}function isDate (year, month, day){// month argument must be in the range 1 - 12month = month - 1; // javascript month range : 0- 11var tempDate = new Date(year,month,day);if ( (year2k(tempDate.getFullYear()) == year) && (month == tempDate.getMonth()) && (day == tempDate.getDate()) ){ return true;}else{return false;}}function year2k(d) { return (d < 1000) ? d + 1900 : d;}var stime = new Date();stime.setFullYear(health.year.value);stime.setMonth(health.month.value-1);stime.setDate(health.day.value);var yue = health.mweek.value;var true_number=280;if (yue<28){true_number=280-(28-yue);}else if (yue>28){true_number=280+(yue-28);}else if (yue==28){true_number=280;}if (health.mweek.value!=''){var temptime=stime.getTime();stime.setTime((stime.getTime()+ true_number*24*3600*1000))var yuchan = stime.getFullYear()+"-"+(stime.getMonth()+1)+"-"+stime.getDate();var nowt = new Date();var chatime = nowt.getTime()-temptime;var chaweek = Math.floor((chatime)/(1000*60*60*24*7));var chaweek_1 = Math.floor((chatime)/(1000*60*60*24));if (chaweek<0) chaweek=0;if (chaweek_1>(true_number+14)) alert("你的预产期已过!");document.health.yuchan.value = yuchan;document.health.yuchan2.value = chaweek;return false;}}