Introduction to how to calculate what day of the week a certain day is using JavaScript-JS Tutorial-php.cn

Introduction to how to calculate what day of the week a certain day is using JavaScript

巴扎黑

Release： 2017-09-14 11:39:38

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本文实例讲述了JavaScript计算某一天是星期几的方法。分享给大家供大家参考。具体如下：

JavaScript计算某一天是星期几，文本框中是默认值，只要按此种格式输入日期时间，就可以推算出当天是星期几，一个简单的JS时间计算实例，运行本效果后，只需点击“计算”按钮即可显示效果，这样我们就能很快的知道某一天是星期几了。

运行效果图如下：

&lt;html>
&lt;head>
&lt;title>计算某一天是星期几&lt;/title>
&lt;style type="text/css">
.style5 {font-size: 12px}
&lt;/style>
&lt;/head>
&lt;script language="javascript">
function checktext()
{
 if((form1.yeartext.value == "") && (form1.monthtext.value == "") && (form1.datetext.value == ""))
 {
 alert("请输入相关信息!");
 form1.yeartext.focus();return;
 }
 if((form1.yeartext.value.length !=4 ) && (form1.monthtext.value.length !=1 ) && (form1.datetext.value.length !=1 ))
 {
 alert("输入错误，只能输入4位数！");
 form1.yeartext.focus();return;
 }
}
function mod(x, x_p)
{
 for (var i=x; i>=x_p; i -= x_p);
 return i;
}
function getday()
{
 var currentyear = parseInt(form1.yeartext.value,10);
 var currentmonth = parseInt(form1.monthtext.value,10);
 var currentday = parseInt(form1.datetext.value,10);
 var sig_val;
 var begindate = new Array(0,3,3,6,1,4,6,2,5,0,3,5);
 var rundate = new Array(-1,2,2,5,0,3,5,1,4,-1,2,4);
 var Pmonth = new Array(29,31,28,31,30,31,30,31,31,30,31,30,31)
 var montharray = new Array("星期日","星期一","星期二","星期三","星期四","星期五","星期六");
 sig_val =begindate[currentmonth - 1];
 var val1 = mod((currentyear + parseInt(currentyear/4) + currentday + sig_val)-2,7);
 var M=parseInt(document.all.monthtext.value);
 var D=parseInt(document.all.datetext.value);
 if ((currentyear%4==0 && currentyear%100!=0)||(currentyear%400==0))
 {
 if ((M&lt;13)&&(M>0)){
  if ((M==2)&&(D>Pmonth[0])){alert("输入错误");document.all.resulttext.value="";}
  else{
  if ((D>Pmonth[M])&&(M!=2)){alert("输入错误");document.all.resulttext.value="";}
  else{
  sig_val =rundate[currentmonth - 1];
  val1 = mod((currentyear + parseInt(currentyear/4) + currentday + sig_val)-2,7);
  if (M>2){val1+=1;}
  form1.resulttext.value =montharray[val1];
  }
  }
 }else{alert("输入错误");document.all.resulttext.value="";}
 }
 else
 {
 if ((M&lt;13)&&(M>0)){
  if (D>Pmonth[M]){alert("输入错误");document.all.resulttext.value="";}
  else{form1.resulttext.value =montharray[val1];}
 }else{alert("输入错误");document.all.resulttext.value="";}
 }
}
&lt;/script>
&lt;body>
&lt;center>
&lt;form name="form1" method="post" action="">
 &lt;table width="308" border="1" cellpadding="3" cellspacing="1" bordercolor="#33CCFF" bgcolor="#CCFFFF">
   &lt;tr bgcolor="#FFFFFF">
    &lt;td align="center" class="style5">输入年：&lt;/td>
    &lt;td width="170">&lt;input name="yeartext" type="text" id="yeartext" value="2016">&lt;/td>
   &lt;/tr>
   &lt;tr bgcolor="#FFFFFF">
    &lt;td align="center" class="style5">输入月：&lt;/td>
    &lt;td>&lt;input name="monthtext" type="text" value="2">&lt;/td>
   &lt;/tr>
   &lt;tr bgcolor="#FFFFFF">
    &lt;td align="center" class="style5">输入日：&lt;/td>
    &lt;td>&lt;input name="datetext" type="text" value="2">&lt;/td>
   &lt;/tr>
   &lt;tr bgcolor="#FFFFFF">
    &lt;td align="center">&lt;span class="style5">星  期：&lt;/span>&lt;/td>
    &lt;td>&lt;input name="resulttext" type="text" id="resulttext">&lt;/td>
   &lt;/tr>
   &lt;tr align="center" bgcolor="#FFFFFF">
    &lt;td colspan="2">
 &lt;p align="right">
     &lt;input name="enter" type="button" value="计算" onClick="checktext();getday();">
    &lt;/p>
&lt;/td>
   &lt;/tr>
  &lt;/table>
 &lt;/form>
&lt;/center>
&lt;/body>
&lt;/html>

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