If you fix your missing "
in <div id="days-container">
the JavaScript runs.
let yearChosen=new Date().getFullYear();
let monthChosen=new Date().getMonth();
let months=["January","February","March","April","May",
"June","Jully","August","September","Octomber","November","December"];
function getNumberOfDays(year,month) {
let numDays=new Date(year,month+1,0).getDate();
return numDays;
}
function renderCal(getNumDays) {
let yearPTag=document.getElementById("year");
yearPTag.innerText=yearChosen;
let monthName=months[monthChosen];
let monthPTag=document.getElementById("month");
monthPTag.innerText=monthName;
for(i=1;i<=getNumDays; i++) {
let dayPTag=document.createElement("p");
let dayText=document.createTextNode(i.toString());
dayPTag.appendChild(dayText);
let date=monthName+""+i.toString()+","+yearChosen;
let dayOfWeek=new Date(date).getDay();
document.getElementById(dayOfWeek).appendChild(dayPTag);
}
}
renderCal(getNumberOfDays(yearChosen,monthChosen));
#cal-container{
width:300px;
height:500px;
border:1px solid black;
margin:400px;
margin-left:500px;
}
#cal-header{
display:flex;
justify-content:space-around;
}
p{
display:inline;
}
<head>
<title>Calendar</title>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width,initial-scale-1.0">
</head>
<body>
<div id="cal-container">
<div id="cal-header">
<div>
<i><</i>
<p id="month"></p>
<i>></i>
</div>
<div>
<i><</i>
<p id="year"></p>
<i>></i>
</div>
</div>
<div id="days-container">
<div id="0" class="days-column"></div>
<div id="1" class="days-column"></div>
<div id="2" class="days-column"></div>
<div id="3" class="days-column"></div>
<div id="4" class="days-column"></div>
<div id="5" class="days-column"></div>
<div id="6" class="days-column"></div>
</div>
</div>
</body>