Question

如何在输入中获取文本插入符号的索引？

Answer 1

<!doctype html>

<html>
    <head>
        <meta charset = "utf-8">

        <script type = "text/javascript">
            window.addEventListener ("load", function () {
                var input = document.getElementsByTagName ("input");

                input[0].addEventListener ("keydown", function () {
                    alert ("Caret position: " + this.selectionStart);

                    // You can also set the caret: this.selectionStart = 2;
                });
            });
        </script>

        <title>Test</title>
    </head>

    <body>
        <input type = "text">
    </body>
</html>

Answer 2

以下内容将为您提供选择的开头和结尾作为字符索引。它适用于文本输入和textareas，并且由于IE对换行符的奇怪处理而略显复杂。

function getInputSelection(el) {
    var start = 0, end = 0, normalizedValue, range,
        textInputRange, len, endRange;

    if (typeof el.selectionStart == "number" && typeof el.selectionEnd == "number") {
        start = el.selectionStart;
        end = el.selectionEnd;
    } else {
        range = document.selection.createRange();

        if (range && range.parentElement() == el) {
            len = el.value.length;
            normalizedValue = el.value.replace(/\r\n/g, "\n");

            // Create a working TextRange that lives only in the input
            textInputRange = el.createTextRange();
            textInputRange.moveToBookmark(range.getBookmark());

            // Check if the start and end of the selection are at the very end
            // of the input, since moveStart/moveEnd doesn't return what we want
            // in those cases
            endRange = el.createTextRange();
            endRange.collapse(false);

            if (textInputRange.compareEndPoints("StartToEnd", endRange) > -1) {
                start = end = len;
            } else {
                start = -textInputRange.moveStart("character", -len);
                start += normalizedValue.slice(0, start).split("\n").length - 1;

                if (textInputRange.compareEndPoints("EndToEnd", endRange) > -1) {
                    end = len;
                } else {
                    end = -textInputRange.moveEnd("character", -len);
                    end += normalizedValue.slice(0, end).split("\n").length - 1;
                }
            }
        }
    }

    return {
        start: start,
        end: end
    };
}

var textBox = document.getElementById("textBoxId");
textBox.focus();
alert( getInputSelection(textBox).start );

Answer 3

现在有一个很好的jQuery插件：Caret plugin

然后你可以拨打$("#myTextBox").caret();

Answer 4

我们在旧的javascript应用程序中使用了类似的东西，但我在几年内没有测试过它：

function getCaretPos(input) {
    // Internet Explorer Caret Position (TextArea)
    if (document.selection && document.selection.createRange) {
        var range = document.selection.createRange();
        var bookmark = range.getBookmark();
        var caret_pos = bookmark.charCodeAt(2) - 2;
    } else {
        // Firefox Caret Position (TextArea)
        if (input.setSelectionRange)
            var caret_pos = input.selectionStart;
    }

    return caret_pos;
}

Answer 5

在文本框中获取光标的工作示例：

function textbox()
{
    var ctl = document.getElementById('Javascript_example');
    var startPos = ctl.selectionStart;
    var endPos = ctl.selectionEnd;
    alert(startPos + ", " + endPos);
}

在HTML输入中获取插入位置？

5 个答案: