在文本框上按Delete或Backspace键可删除字符或文本 [英] Getting deleted character or text on pressing delete or backspace on a textbox

问题描述

我有一个文本框，我想在按Backspace键或Delete键时获取已删除的字符.

I have a text box, I want to get the deleted character when I press a backspace or delete key.

我有一个按键事件处理程序，并且我正在捕获按键是否为退格键.现在在其中，我需要根据已删除的密钥执行一些任务.请帮忙.

I have a key up event handler and i am capturing if the key is backspace. Now inside this I need to perform some tasks based on the key deleted. Please help.

推荐答案

在

After making a little tweak for the getCursorPosition function in this thread, you can get the characters deleted by tracking the current cursor selection.

代码处理以下情况:

1. 键入，然后在末尾退格.
2. 将光标移到文本的中间并删除/退格.
3. 选择一段文本，然后删除/退格.

$.fn.getCursorPosition = function() {
    var el = $(this).get(0);
    var pos = 0;
    var posEnd = 0;
    if('selectionStart' in el) {
        pos = el.selectionStart;
        posEnd = el.selectionEnd;
    } else if('selection' in document) {
        el.focus();
        var Sel = document.selection.createRange();
        var SelLength = document.selection.createRange().text.length;
        Sel.moveStart('character', -el.value.length);
        pos = Sel.text.length - SelLength;
        posEnd = Sel.text.length;
    }
    // return both selection start and end;
    return [pos, posEnd];
};

$('#text').keydown(function (e) {
    var position = $(this).getCursorPosition();
    var deleted = '';
    var val = $(this).val();
    if (e.which == 8) {
        if (position[0] == position[1]) {
            if (position[0] == 0)
                deleted = '';
            else
                deleted = val.substr(position[0] - 1, 1);
        }
        else {
            deleted = val.substring(position[0], position[1]);
        }
    }
    else if (e.which == 46) {
        var val = $(this).val();
        if (position[0] == position[1]) {

            if (position[0] === val.length)
                deleted = '';
            else
                deleted = val.substr(position[0], 1);
        }
        else {
            deleted = val.substring(position[0], position[1]);
        }
    }
    // Now you can test the deleted character(s) here
});

这是 实时演示

这篇关于在文本框上按Delete或Backspace键可删除字符或文本的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！