jquery随机生成整数

 <tr><td>年龄: <input type="text" name="age" size="5" id="age" disabled>td>tr>
            <script src="http://ajax.googleapis.com/ajax/libs/jquery/1.8.0/jquery.min.js">
                $document.ready(function(){
                    var x=80;
                    var y=18;
                    var rand=parseInt(Math.random()*(x-y+1)+y);
                    form1.age.value=rand;
                })
        script>

想生成随机的年龄 在年龄输入框里 但是都是空白

赋值语句不对吧，应该是：$("#age").val("需赋值的内容")

使用国内jq cdn

<!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>Document</title>
</head>
<body>
  <tr><td>年龄: <input type="text" name="age" size="5" id="age" disabled></td></tr>
  <script src="http://code.jquery.com/jquery-1.11.0.min.js"></script>
  <script>
    let x=80;
    let y=18;
    let rand=parseInt(Math.random()*(x-y+1)+y);
    let $age = $("#age");
    $age.val(rand);
</script> 
</body>
</html>