JQuery Calendar Widget

index.html

 <h1>Simple Calendar Widget</h1>
<div class = "wrapper">
 
  <label for = "date">Date:</label>
  <input id = "date"/>
   <span class = "calendar-icon"></span>
  <div class = "calendar">
    <span class = "month-prev"></span>
    <h2 id = "month" class = "month"></h2>
    <span class = "month-next"></span>
    <ol class = "weekdays">
      <li>Sun</li>
      <li>Mon</li>
      <li>Tue</li>
      <li>Wed</li>
      <li>Thu</li>
      <li>Fri</li>
      <li>Sat</li>
    </ol>
    <div id = "days" class = "days"></div>
  </div>

JQuery-Calendar-Widget.markdown

JQuery Calendar Widget

Simple JQuery Calendar Widget using moment.js

A Pen by James Barnett on CodePen.

License.

script.js

$(document).ready(function() {
  var timeframe = moment();
  var dayOfWeekOffset = 0;
  var date = moment();
  
  drawCalendar();
  
  function drawCalendar(){
    var output = "<ol>";
    var days = moment(timeframe).daysInMonth();
    var monthName = moment(timeframe).format("MMMM");
    var startOfMonth = moment(timeframe).startOf('month');
    
    /* Find the day of the week the month starting on 
  so we can calculate the offset for days of the week to line up correctly */
    dayOfWeekOffset = parseInt(moment(startOfMonth).format("d"),10);
    
    /* draw offset */
    for (i = 0; i < dayOfWeekOffset; i++) {
      output += "<li>";
      output += "</li>";
    }
    
    /*** draw days ***/  
    for (i = 1; i <= days; i++) {
      output += "<li>";
      output += i;
      output += "</li>";
    }
    
    output += "</ol>";
    document.getElementById("days").innerHTML = output;
    
    monthName = moment(timeframe).format("MMMM YYYY");
    document.getElementById("month").innerHTML = monthName;
    
    markToday();
    getSelectedDay();
  }
  
  function getSelectedDay(){
    $(".days li").click(function() {
      var myDay = $(this).text();
      
      /* make sure user clicked on an actual day not one of the offset boxes */
      if (!isNaN(parseInt(myDay, 10))){
        var myMonth = moment(timeframe).format("M");
        var myYear = moment(timeframe).format("YY");
        $("input").val(myMonth + "/" + myDay + "/" + myYear);
        styleDateValidation();
        styleSelectedDay();
      }
    });
  }
  
  function markToday(){
    var dayOfMonth = moment().format("D");
    var today =  dayOfWeekOffset + parseInt(dayOfMonth, 10);
    
    
    /* because today is calculated using the day of month, double check it's the current month */
    if (moment(timeframe).isSame(moment(), 'month')){
      $( ".days li:nth-Child(" + today + ")" ).addClass( "today" );
    } 
  }
  
  /* parse date from input field & re-draw calendar*/
  function parseDate(){
    var dateRaw = $("input").val();
    date = moment(dateRaw).format("YYYY-MM-DD");
    if(date !== "Invalid date"){
      timeframe = moment(date);
      drawCalendar();
      styleSelectedDay();
      return true;
    } else { return false; }
  }
  
  /* style input box to indicate a valid/invalid date */
  function styleDateValidation(){
    if (parseDate() === true) { 
      if ($("input").hasClass( "valid-date" ) !== true) {
        $("input").addClass("valid-date");
      }
      if ($("input").hasClass( "invalid-date" ) === true) {
        $("input").removeClass("invalid-date");
      }
    } else {
      if ($("input").hasClass( "invalid-date" ) !== true) {
        $("input").addClass("invalid-date");
      }
      if ($("input").hasClass( "valid-date" ) === true) {
        $("input").removeClass("valid-date");
      }
    }
  }
  
  function styleSelectedDay(){
    var selectedDayRaw = moment(date).format("D");
    if (!isNaN(parseInt(selectedDayRaw, 10))){
      var selectedDay =  dayOfWeekOffset + parseInt(selectedDayRaw, 10);
      $( ".days li:nth-Child(" + selectedDay + ")" ).addClass( "selected-day" );
    }
  }
  
  $(".calendar-icon").click(function() {
    $(".calendar").toggle();
  });
  
  $("input").click(function() {
    $(".calendar").show();
  });
  
  $("input").keyup(function() {
    styleSelectedDay();
    styleDateValidation();
  });
  
  /*** change month on calendar ***/
  $(".month-next").click(function() {
    timeframe = moment(timeframe).add('M', 1).format("YYYY-MM-DD");
    drawCalendar();
  });
  
  $(".month-prev").click(function() {
    timeframe = moment(timeframe).subtract('M', 1).format("YYYY-MM-DD");
    drawCalendar();
  });
  
});

style.css

@import url(http://netdna.bootstrapcdn.com/font-awesome/3.2.1/css/font-awesome.css);

ol, li { margin: 0; padding: 0; list-style: none; }
.wrapper {  
  width: 330px; 
  margin: 10px 40px; 
}

h1 { 
  font-size: 1.5em; 
  margin-left: 20px;
}

label { margin: auto; }
input { margin: 0 0 10px 10px;}
.calendar {
  display: none;
  margin-left: 5px;
  width: 255px;
  color: #525252;
}

.days li:hover, .month-prev:hover, .month-next:hover, .calendar-icon { cursor: pointer; }
.month, .month-prev, .month-next, .calendar-icon { font-size: 1.125em; }
.month { 
  width: 185px;
  display: inline-block;
  margin: 0;
  text-align: center; 
}

.month-prev, .month-next, .calendar-icon { 
  font-family: FontAwesome;
  padding: 3px;
  display: inline-block;
}

.calendar-icon:before { 
  content: "\f073"; 
  margin-left: 5px;
}

.month-prev:before { 
  content: "\f0a8"; 
  margin-left: 5px;
}

.month-next:before { 
  content: "\f0a9"; 
  margin-right: 5px;
}

.weekdays li, .days li { 
  font-size: 13px;
  text-align: center;
}

.weekdays li { 
  width: 20px;
  padding: 0 6px 5px 3px;
  margin-left: 2px;
  display: inline-block; 
}

.days li {
  width: 20px;
  height: 20px;
  float: left;
  padding: 5px 5px 5px 10px;
  
  font-size: 13px;
  font-family: Tahoma, Verdana, sans-serif;
  font-weight: bold;
}

.days li:hover { 
  color: royalblue;
  background: whitesmoke;
}

.today { 
  color: indianred; 
  background: whitesmoke;
}

/*** draw borders ***/

.days li {
  border-bottom: 1px solid darkgrey;
  border-right: 1px solid darkgrey;
}

.days li:nth-child(-n+7) { border-top: 1px solid darkgrey; }
.days li:nth-child(7n+1) { border-left: 1px solid darkgrey; }

/*** valid/invalid date field ***/
.valid-date {
  outline: none;
  border: 2px solid green;
}

.invalid-date {
  outline: none;
  border: 2px solid red;
}

.selected-day { 
  background: whitesmoke; 
  color: green;
}