Java Script Array Methods

    <!DOCTYPE html>
    <html lang="en">
    <head>
        <meta charset="UTF-8">
        <meta http-equiv="X-UA-Compatible" content="IE=edge">
        <meta name="viewport" content="width=device-width, initial-scale=1.0">
        <title>Java Script Array Methods</title>
        <style>
    input
    {
        width:300px;
    }
    
        </style>
        <script>
            function f1()
            {
                
                document.getElementById("t1").value=[1,2,3,4].at(3);
            }
            function f2()
            {
                let a=[1,2,3,4];
                document.getElementById("t2").value="Popped element = " + a.pop() + ", Array = " + a;
            }
            function f3()
            {
                let a=[1,2,3,4];
                document.getElementById("t3").value="Pushed element = " + a.push(5) + ", Array = " + a;;
            }
            function f4()
            {
                let a=[1,2,3,4];
                document.getElementById("t4").value="Filled element = " + a.fill(5) + ", Array = " + a;;
            }
            function f5()
            {
                let a=[1,2,3,4];
                document.getElementById("t5").value="Return = " + a.reverse() + ", Array = " + a;;
            }
            function f6()
            {
                let a=[1,2,3,4];
                document.getElementById("t6").value="Return = " + a.shift() + ", Array = " + a;;
            }
            function f7()
            {
                let a=[1,2,3,4];
                document.getElementById("t7").value="Return = " + a.unshift(5) + ", Array = " + a;;
            }
            function f8()
            {
                let a=[1,2,3,4];
                document.getElementById("t8").value="Return = " + a.includes(3) + ", Array = " + a;;
            }
            function f9()
            {
                let a=[1,2,3,4];
                document.getElementById("t9").value="Return = " + a.map(n => n + 2) + ", Array = " + a;;
            }
            function f10()
            {
                let a=[1,2,3,4];
                document.getElementById("t10").value="Return = " + a.some(n => n > 2) + ", Array = " + a;;
            }
            function f11()
            {
                let a=[1,2,3,2,4];
                document.getElementById("t11").value="Return = " + a.find(n => n>5) + ", Array = " + a;;
            }
            function f12()
            {
                let a=[1,2,3,2,4];
                document.getElementById("t12").value="Return = " + a.every(n => n<30) + ", Array = " + a;;
            }
            function f13()
            {
                let a=[1,2,3,2,4];
                document.getElementById("t13").value="Return = " + a.filter(n => n<30) + ", Array = " + a;;
            }
        </script>
    </head>
    <body>
        <h2>Code</h2>
        <div>
    <textarea>