<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script>
<!-- Latest compiled and minified CSS -->
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css" integrity="sha384-BVYiiSIFeK1dGmJRAkycuHAHRg32OmUcww7on3RYdg4Va+PmSTsz/K68vbdEjh4u" crossorigin="anonymous">
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<link rel="stylesheet" type="text/css" href="MyCode/css/style.css">
</head>
<body>
<div id="header">
<div id="logo">
<b>MyCode</b>
<!-- <i><span style="font-size:12px;">Make learning code approachable</span><i> -->
</div>
<br>
<div id="footnote">
-Make learning code approachable
</div>
<div id="buttonContainer">
<div class="toggleButton " id="html">HTML</div>
<div class="toggleButton" id="css">CSS</div>
<div class="toggleButton" id="javascript">JavaScript</div>
<div class="toggleButton " id="output">Output</div>
</div>
</div>
<div id="bodyContainer">
<textarea id="htmlPanel" class="panel"><p id="paragraph">Hello World!</p></textarea>
<textarea id="cssPanel" class="panel hidden">p { color: green; }</textarea>
<textarea id="javascriptPanel" class="panel hidden">document.getElementById("paragraph");</textarea>
<iframe id="outputPanel" class="panel"></iframe>
</div>
</body>
<script type="text/javascript">
function updateOutput() {
$("iframe").contents().find("html").html("<html><head><style type='text/css'>" + $("#cssPanel").val() + "</style></head><body>" + $("#htmlPanel").val() + "</body></html>");
document.getElementById("outputPanel").contentWindow.eval($("#javascriptPanel").val());
}
$(".toggleButton").click(function() {
var panelId = $(this).attr("id") + "Panel";
$("#" + panelId).toggleClass("hidden");
var numberOfActivePanels = 4 - $('.hidden').length;
$(".panel").width(($(window).width() / numberOfActivePanels) - 10);
})
$(".panel").height($(window).height() - $("#header").height() - 15);
$(".panel").width(($(window).width() / 2) - 10);
updateOutput();
$("textarea").on('change keyup paste', function() {
updateOutput();
});
</script>