function yunchan() {
	var year = document.getElementById('wyear');
	var month = document.getElementById('wmonth');
	var day = document.getElementById('wday');
	if (year.value == "" || month.value == "" || day.value == "") {
		alert("请填写完整年月日!");
		return;
	}
	if (year.value > 2050 || year.value < 1990) {
		alert("请填写正确年份!");
		year.focus();
		return;
	}
	if (month.value > 12 || month.value < 1) {
		alert("请填写正确月份!");
		month.focus();
		return;
	}
	if (day.value > 31 || day.value < 1) {
		alert("请填写正确日子!");
		day.focus();
		return;
	}
	if (!isDate(year.value, month.value, day.value)) {
		alert("年月日组合有错,请重新填写!");
		return;
	}
	
	function isDate(year, month, day) {
		// month argument must be in the range 1 - 12
		month = month - 1;  // javascript month range : 0- 11
		var tempDate = new Date(year, month, day);
		if ((year2k(tempDate.getFullYear()) == year) && (month == tempDate.getMonth()) && (day == tempDate.getDate())) {
			return true;
		} else {
			return;
		}
	}
	
	function year2k(d) {
		return (d < 1000) ? d + 1900 : d;
	}
	
	var stime = new Date();
	stime.setFullYear(year.value);
	stime.setMonth(month.value - 1);
	stime.setDate(day.value);
	
	var yue = document.getElementById('wperiod').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 (yue.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!");
			return null;
		}
		document.getElementById('wtext').innerHTML = '您的预产期是 <b class="red">'+yuchan+'</b>；现在正处于孕期的第 <b class="red">'+chaweek+'</b> 周';
		document.getElementById('wresult').style.display = '';
		
		var c = document.getElementById('wresult').innerHTML;
		var i = '';
		return {c:c, i:i};
	} else {
		return null;
	}

}

function wInit() {
	document.getElementById('wresult').style.display = 'none';
	var d = new Date();
	d.setMonth(d.getMonth() - 8);
	document.getElementById('wyear').value = d.getFullYear();
	document.getElementById('wmonth').value = d.getMonth() + 1;
	document.getElementById('wday').value = d.getDate();
	document.getElementById('wyear').onclick = function(event) {WdatePicker({dateFmt:'yyyy',minDate:'1901', maxDate:'2050'})};
	document.getElementById('wmonth').onclick = function(event) {WdatePicker({dateFmt:'M'})};
	document.getElementById('wday').onclick = function(event) {WdatePicker({dateFmt:'d'})};
	var p = document.getElementById('wperiod');
	for (var i = 20; i <= 45; i++) {
		p.options.add(new Option(i + '天', i));
	}
	p.options[8].selected = true;
}

function handleWork(obj) {
	var v = obj.value;
	obj.disabled = true;
	obj.value = '已出结果';
	
	// global callback
	handleBegin();
	
	var res = yunchan();
	
	if (typeof res == 'object' && res != null) {
		// global callback
		handleFinish(res.c, res.i);
	}
	
	obj.value = v;
	obj.disabled = false;
}