    <!DOCTYPE html>
    <html>
    <head>
      <meta charset="UTF-8">
      <title>Array 객체의 메서드 사용하기</title>
      <link rel="stylesheet" href="style_js.css">
    <body>
      <script>
        let a1 = [0, 1, 2, 3, 4];
        let a2 = new Array(9, 8, 7, 6, 5);
        document.write(`a1 = [${a1}]<br>`);
        document.write(`a2 = [${a2}]<hr>`);

        document.write(`a1.concat(a2) : ${a1.concat(a2)}<hr>`);
        function gt(e) { return(e >= 7) };
        document.write(`a2.filter(gt) : ${a2.filter(gt)}<hr>`);
        document.write(`a2.indexOf(6) : ${a2.indexOf(6)}<hr>`);
        a2.push(4);
        document.write(`a2.push(4) : ${a2}<hr>`);
        a2.pop();
        document.write(`a2.pop() : ${a2}<hr>`);
        document.write(`a1.reverse() : ${a1.reverse()}<hr>`);
        a2.shift();
        document.write(`a2.shift() : ${a2}<hr>`);
        a2.unshift(9);
        document.write(`a2.unshift(9) : ${a2}<hr>`);
        document.write(`a2.slice(1,4) : ${a2.slice(1,4)}<hr>`);
        document.write(`a2.sort() : ${a2.sort()}<hr>`);
        document.write(`a2.join("+") : ${a2.join("+")}`);
      </script>
    </body>
    </html>