如何解决$ write.val的错误不是函数？

Question

早上好，

我只是接近我的结果，我在控制台上出错了

1.write不是一个函数 2. $ write.val不是函数

如何解决此错误我如何在我的代码中编写函数。如何$ write.val不是定义它的函数以及我如何解决这种类型的错误。

这是代码

$(function() {
    /*$(":input").map((i, el) => el.id).get(),*/
    //var abc = abc();
    //var abc;
    var $write = $(":input").bind('focus', function() {
        $write = $(this).attr('id');
        //console.log(Object.values($write));
        //console.log($write);

        //});   
        //var test=abc();  // this will grab you the return value from firstFunction();
        //alert(test);
        var $write = $write;
        shift = false,
            capslock = false;
        alert($write);
        //console.log(Object.values($write));

        $('#keyboard li').click(function() {
            var $this = $(this),
                character = $this.html(); // If it's a lowercase letter, nothing happens to this variable

            // Shift keys
            if ($this.hasClass('left-shift') || $this.hasClass('right-shift')) {
                $('.letter').toggleClass('uppercase');
                $('.symbol span').toggle();

                shift = (shift === true) ? false : true;
                capslock = false;
                return false;
            }

            // Caps lock
            if ($this.hasClass('capslock')) {
                $('.letter').toggleClass('uppercase');
                capslock = true;
                return false;
            }

            // Delete
            if ($this.hasClass('delete')) {
                var html = $write.html(),
                    txt = html.substr(0, html.length - 1);
                $write.html(txt);
                $write.autocomplete("search", txt);
                return false;
            }

            // Special characters
            if ($this.hasClass('symbol')) character = $('span:visible', $this).html();
            if ($this.hasClass('space')) character = ' ';
            if ($this.hasClass('tab')) character = "\t";
            if ($this.hasClass('return')) character = "\n";

            // Uppercase letter
            if ($this.hasClass('uppercase')) character = character.toUpperCase();

            // Remove shift once a key is clicked.
            if (shift === true) {
                $('.symbol span').toggle();
                if (capslock === false) $('.letter').toggleClass('uppercase');

                shift = false;
            }

            // Add the character
            $write.val($write.val() + character);
            $write.html(txt);
            $write.autocomplete("search", txt);
        });
    });
});

这是代码的其余部分

 $(function () {
     var write = write();   
     write.init("keyboard");
     //first input focus
     var $firstInput = $(":input").first().focus();
     write.currentElement = $firstInput;
     write.currentElementCursorPosition = 0;
 });