笔记指定n天间距日期的计算

水深无声 2022-06-05 03:14 299阅读 0赞

原理很简单，一天的时间的毫秒数是1000*60*60*24，前n天的日期就是现在日期换成毫秒-n*1000*60*60*24。再把这个值换成日期即可（通过setTime方法）

var newDate = new Date(); var end_date = ""+ newDate.getFullYear()+"-"+(newDate.getMonth()+1)+"-"+(newDate.getDate()+1)+"" $(".end_date").val(end_date); var time = newDate.getTime(); var startdate = new Date(time - 60*1000*60*60*24); var start_date = startdate.getFullYear()+"-"+ (startdate.getMonth()+1)+"-"+ startdate.getDate(); $(".start_date").val(start_date);

[?][Link 1]

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     <pre><code><span style="font-family:Times New Roman;font-size:14px;">&lt;body&gt; &lt;select id="num"name="num"style="width:150px"οnchange="ff()"&gt; &lt;option value="-1"&gt;昨天&lt;/option&gt; &lt;option value="0"&gt;今天&lt;/option&gt; &lt;option value="1"&gt;明天&lt;/option&gt; &lt;/select&gt;&lt;br&gt; &lt;textarea id="ar"rows="3"cols="20"&gt; haha &lt;/textarea&gt; &lt;br/&gt; &lt;input type="text"value=""name="bday"id="bday"/&gt;天之前 &lt;input type="button"οnclick="bday()"value="计算"&gt;&lt;br/&gt; &lt;input type="text"value=""name="aday"id="aday"/&gt;天之后 &lt;input type="button"οnclick="aday()"value="计算"&gt;&lt;br/&gt; &lt;/body&gt; &lt;script&gt; ff(); functionff(){ varobj=document.getElementById("num"); varv1=obj.options[obj.selectedIndex].text; varv2=obj.options[obj.selectedIndex].value; vartvv=giveDateStr(getTargetday(v2)); document.getElementById('ar').innerText=tvv; } functionisInteger(obj) { varr = /^\+?[1-9][0-9]*$/;　　//正整数 returnr.test(obj); } functionbday(){ varbef=document.getElementById("bday").value; if(isInteger(bef)){ varbvv=giveDateStr(getTargetday(-bef)); document.getElementById('ar').innerText=bvv; }else{ alert("请输入正整数！"); document.getElementById("bday").value=''; document.getElementById("bday").focus(); } } functionaday(){ varatf=document.getElementById("aday").value; if(isInteger(atf)){ varavv=giveDateStr(getTargetday(atf)); document.getElementById('ar').innerText=avv; }else{ alert("请输入正整数！"); document.getElementById("aday").value=''; document.getElementById("aday").focus(); } } functiongetTargetday(num){ varnumber=null; if(num==null||num==0){ number=0; }else{ number=num; } var today=new Date(); var targetday_milliseconds=today.getTime()+1000*60*60*24*number; var targetday=new Date(); targetday.setTime(targetday_milliseconds);//注意，这行是关键代码 returntargetday; } functiongiveDateStr(dd){ varriqiyue=dd.getMonth()+1; varriqihao=dd.getDate(); varriqixingqi=null; if(dd.getDay()=='0'){ xingqi="星期日"; }elseif(dd.getDay()=='1'){ xingqi='星期一'; }elseif(dd.getDay()=='2'){ xingqi='星期二'; }elseif(dd.getDay()=='3'){ xingqi='星期三'; }elseif(dd.getDay()=='4'){ xingqi='星期四'; }elseif(dd.getDay()=='5'){ xingqi='星期五'; }elseif(dd.getDay()=='6'){ xingqi='星期六'; } varriqi=riqiyue+"月"+riqihao+"日"+"("+xingqi+")"; returnriqi; } &lt;/script&gt; &lt;/html&gt;</span></code></pre> 
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[Link 1]: http://www.jb51.net/article/124795.htm#