jQuery textarea.val（''）在FIRST Enter上添加换行符吗？

Question

I have a little chat setup, and on enter press if the text area is in focus I have it set to submit the chat to my database and clear the text area. Unfortunately though, the first time one presses enter it adds a linebreak in the text area, in any browser. If you type and press enter again, there's still only one line break there. Am I missing something?

Thanks!

    $(document).keypress(function(keyPress) {
        if (keyPress.which == 13) {
            if ($('#chatText').is(':focus')) {
                if ($('#chatText').val().length > 0) {
                    chatValue = $('#chatText').val();
                    $('#chatText').val($('#chatText').val().substring(0,0));
                    $.ajax({
                        type: 'POST',
                        url: 'submitChat.php',
                        data: { chatText: chatValue },
                        success: function(result) {
                            $('#chat_text').html(result);
                            document.getElementById('chat_text').scrollTop = 9999999;
                        }
                    });
                }
            }
        }
    });

Answer 1

Why don't you just clear it?

$('#chatText').keypress(function(e) {
    if (e.which == 13) {
        var value = $(this).val();

        if (value.length > 0) {
            $(this).val('');

            $.ajax({
                type: 'POST',
                url: 'submitChat.php',
                data: {
                    chatText: value
                },
                success: function(result) {
                    $('#chat_text').html(result);
                    this.scrollTop = 9999999;
                }
            });
        }
    }
});

Answer 2

Try this,

$(document).keypress(function(keyPress) {
            if (keyPress.which == 13) {
                keyPress.preventDefault();
                if ($('#chatText').is(':focus')) {
                    if ($('#chatText').val().length > 0) {
                        chatValue = $('#chatText').val();
                        $('#chatText').empty();
                        $.ajax({
                            type: 'POST',
                            url: 'submitChat.php',
                            data: { chatText: chatValue },
                            success: function(result) {
                                $('#chat_text').html(result);
                                document.getElementById('chat_text').scrollTop = 9999999;
                            }
                        });
                    }
                }
            }
        });

Answer 3

 $(document).keypress(function(keyPress) {


        if (keyPress.which == 13) {
            keyPress.preventDefault();// Add this line
            if ($('#chatText').is(':focus')) {
                if ($('#chatText').val().length > 0) {
                    chatValue = $('#chatText').val();
                    $('#chatText').val($('#chatText').val().substring(0,0));
                    $.ajax({
                        type: 'POST',
                        url: 'submitChat.php',
                        data: { chatText: chatValue },
                        success: function(result) {
                            $('#chat_text').html(result);
                            document.getElementById('chat_text').scrollTop = 9999999;
                        }
                    });
                }
            }
        }
    });