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Here you can Sed posuere consectetur est at lobortis. Donec ullamcorper nulla non metus auctor fringilla. Maecenas sed diam eget risus varius blandit sit amet non magna. Donec id elit non mi porta gravida at eget metus. Praesent commodo cursus magna, vel scelerisque nisl consectetur et.

HTML

            
              <div class="calendar-container" id="calendar"></div>
            
          
!

CSS

            
              * {
  box-sizing: border-box;
}
*:before, *:after {
  box-sizing: inherit;
}

.calendar-container {
  width: 600px;
}
.calendar {
  border-bottom: 1px solid rgba(0, 0, 0, .5);
  border-right: 1px solid rgba(0, 0, 0, .5);
  width: 100%;
}
.day {
  border-top: 1px solid rgba(0, 0, 0, .5);
  border-left: 1px solid rgba(0, 0, 0, .5);

  padding: 15px;

  text-align: center;
}
.day.adj-month {
  background-color: rgba(0, 0, 0, .1);
  opacity: .5;
}

.calendar-item {
  display: block;
  height: 5px;

}

.calendar-control {
  background-color: rgb(225, 225, 225);
  border: 1px solid rgba(170, 170, 170, .7);
  cursor: pointer;
  display: inline-block;
  padding: 4px 12px;
}

.calendar-control[data-calendar-control="prev"] {
  float: left;
}
.calendar-control[data-calendar-control="next"] {
  float: right;
}
            
          
!

JS

            
              ;(function() {
  function Calendar(target, date, data) {
    var date
    var calendar
    var container

    switch (typeof date) {
      case 'string':
        date = date.split('-')
        date = new Date(date[0], parseInt(date[1], 10) - 1, date[2])
        break
      case 'undefined':
        date = new Date()
        break
      case 'object':
        if (date instanceof Array) {
          data = date
          date = new Date()
        } else {
          date = date
        }
        break
      default:
        throw 'Invalid date type!'
    }

    container = document.querySelector(target)
    calendar = buildTable(date.getFullYear(), date.getMonth())
    container.appendChild(calendar)
    container.appendChild(buildControls(date))

    function buildTable(year, month) {
      var controlDate = new Date(year, month + 1, 0)
      var currDate = new Date(year, month, 1)
      var iter = 0
      var ready = true

      var table = newElement('table')
      var thead = newElement('thead')
      var tbody = newElement('tbody')
      var tr

      if (currDate.getDay() !== 0) {
        iter = 0 - currDate.getDay()
      }

      while (ready) {
        if (currDate.getDay() === 6) {
          if (tr) {
            tbody.appendChild(tr)
          }
          tr = null
        }

        if (!tr) {
          tr = newElement('tr')
        }

        currDate = new Date(year, month, ++iter)

        tr.appendChild(newDayCell(currDate, iter < 1 || +currDate > +controlDate))

        if (+controlDate < +currDate && currDate.getDay() === 0) {
          ready = false
        }

      }

      thead.innerHTML = '<tr>' +
        '<th class="day">Sun</th>' +
        '<th class="day">Mon</th>' +
        '<th class="day">Tue</th>' +
        '<th class="day">Wed</th>' +
        '<th class="day">Thu</th>' +
        '<th class="day">Fri</th>' +
        '<th class="day">Sat</th>' +
        '</tr>'

      table.appendChild(thead)
      table.appendChild(tbody)

      table.className = 'calendar'
      table.setAttribute('cellspacing', 0)
      table.setAttribute('cellpadding', 0)
      table.setAttribute('data-period', year + '-' + (month))

      return table
    }

    function newDayCell(dateObj, isOffset) {
      var td = newElement('td')
      var number = newElement('span')
      var isoDate = dateObj.toISOString()
      isoDate = isoDate.slice(0, isoDate.indexOf('T'))

      number.innerHTML = dateObj.getDate()
      td.className = isOffset ? 'day adj-month' : 'day'
      td.setAttribute('data-date', isoDate)

      td.appendChild(number)

      for (var i = 0; i < data.length; i++) {
        if (data[i].date === isoDate) {
          var item = newElement('span')
          item.style.backgroundColor = data[i].color
          item.className = 'calendar-item'
          td.appendChild(item)
        }
      }

      return td
    }

    function newElement(tagName) {
      return document.createElement(tagName)
    }

    function buildControls(date) {
      var div = newElement('div')
      var prevBtn = newElement('span')
      var nextBtn = newElement('span')

      prevBtn.innerHTML = '&larr;'
      prevBtn.className = 'calendar-control'
      prevBtn.setAttribute('data-calendar-control', 'prev')

      nextBtn.innerHTML = '&rarr;'
      nextBtn.className = 'calendar-control'
      nextBtn.setAttribute('data-calendar-control', 'next')

      div.className = 'calendar-controls'

      div.appendChild(prevBtn)
      div.appendChild(nextBtn)

      removeEventListener(document, 'click', calendarControlClick)
      addEventListener(document, 'click', calendarControlClick)

      function calendarControlClick(evt) {
        evt.preventDefault()
        if (!evt.target.getAttribute('data-calendar-control')) {
          return
        }

        var target = evt.target

        while (target.parentNode) {
          if (target.parentNode === container) {
            break;
          }

          target = target.parentNode

          if (!target) {
            return
          }
        }

        var action = evt.target.getAttribute('data-calendar-control')

        switch (action) {
          case 'prev':
            date = new Date(date.getFullYear(), date.getMonth() - 1, 1)
            break
          case 'next':
            date = new Date(date.getFullYear(), date.getMonth() + 1, 1)
            break
        }

        calendar = buildTable(date.getFullYear(), date.getMonth())

        container.removeChild(container.firstChild)
        container.insertBefore(calendar, container.firstChild)
      }

      return div
    }

    function addEventListener(target, event, handler) {
      if (document.addEventListener) {
        target.addEventListener(event, handler, false)
      } else {
        target.attachEvent('on' + event, handler)
      }
    }

    function removeEventListener(target, event, handler) {
      if (document.removeEventListener) {
        target.removeEventListener(event, handler, false)
      } else {
        target.detachEvent('on' + event, handler)
      }
    }
  }

  this.calendar = Calendar

}).call(this)

const thisYear = new Date().getFullYear()
var data = [{
  date: `${thisYear}-08-15`,
  title: 'Title A',
  color: '#f00'
}, {
  date: `${thisYear}-08-16`,
  title: 'Title B',
  color: '#f0f'
}, {
  date: `${thisYear}-09-10`,
  title: 'Title C',
  color: '#ff0'
}, {
  date: `${thisYear}-09-01`,
  title: 'Title D',
  color: '#0ff'
}]

calendar('#calendar', data)
            
          
!
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