你如何获得文本区域中的光标位置? [英] How do you get the cursor position in a textarea?

问题描述

我有一个 textarea，我想知道我的光标是在 textarea 的最后一行还是在 textarea 的第一行，并且使用 JavaScript.

I have a textarea and I would like to know if I am on the last line in the textarea or the first line in the textarea with my cursor with JavaScript.

我想到了抓取第一个换行符和最后一个换行符的位置，然后抓取光标的位置.

I thought of grabbing the position of the first newline character and the last newline character and then grabbing the position of the cursor.

var firstNewline = $('#myTextarea').val().indexOf('
');
var lastNewline = $('#myTextarea').val().lastIndexOf('
');

var cursorPosition = ?????;

if (cursorPosition < firstNewline)
    // I am on first line.
else if (cursorPosition > lastNewline)
    // I am on last line.

• 是否可以在 textarea 中抓取光标位置?
• 您是否有更好的建议来确定我是在 textarea 的第一行还是最后一行?

首选 jQuery 解决方案，除非 JavaScript 如此简单或更简单.

jQuery solutions preferred unless JavaScript is as simple or simpler.

推荐答案

如果没有选择，您可以使用属性.selectionStart 或 .selectionEnd(没有选择他们是平等的).

If there is no selection, you can use the properties .selectionStart or .selectionEnd (with no selection they're equal).

var cursorPosition = $('#myTextarea').prop("selectionStart");

请注意，较旧的浏览器不支持此功能，尤其是 IE8-.在那里您必须处理文本范围，但这完全令人沮丧.

Note that this is not supported in older browsers, most notably IE8-. There you'll have to work with text ranges, but it's a complete frustration.

我相信某处有一个库专门用于获取和设置输入元素中的选择/光标位置，不过.我不记得它的名字了，但关于这个主题的文章似乎有几十篇.

I believe there is a library somewhere which is dedicated to getting and setting selections/cursor positions in input elements, though. I can't recall its name, but there seem to be dozens on articles about this subject.

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