点击按钮文本框出现每组7位1-32的随机数

  <input type="text" value="Test" id="Test" />
    <button id="btn">提交</button>
    <script>
        var jschars = ['0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z'];
        function generateMixed(n) {//n代表生成随机数位数
            var res = "";
            for(var i = 0; i < n ; i ++) {
                var id = Math.ceil(Math.random()*35);
                res += jschars[id];
            }
            Test.value=res;
        }
        btn.onclick = function(){
            generateMixed(7) 
        } 
    </script>