<!doctype html>
<html lang="ko">
<head>
<meta charset="utf-8">
<title>jQuery</title>
<script src="//code.jquery.com/jquery-3.3.1.min.js"></script>
<script>
$( document ).ready( function() {
$( '.check-all' ).click( function() {
$( '.ab' ).prop( 'checked', this.checked );
} );
} );
</script>
</head>
<body>
<form>
<p><input type="checkbox" name="all" class="check-all"> <label>Check ALL</label></p>
<hr>
<p><input type="checkbox" name="cb1" class="ab"> <label>Checkbox 1</label></p>
<p><input type="checkbox" name="cb2" class="ab"> <label>Checkbox 2</label></p>
<p><input type="checkbox" name="cb3" class="ab"> <label>Checkbox 3</label></p>
<p><input type="checkbox" name="cb4" class="ab"> <label>Checkbox 4</label></p>
</form>
</body>
</html>
