64

如何在输入中获取文本插入符号的索引？

4

6 回答 6

50

->选择开始

<!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>
于 2011-02-08T02:12:47.730 回答
33

以下将为您提供选择的开始和结束作为字符索引。它适用于文本输入和文本区域，并且由于 IE 对换行符的奇怪处理而稍微复杂一些。

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 );
于 2011-02-08T10:34:32.890 回答
8

现在有一个不错的 jQuery 插件：Caret plugin

然后你可以打电话$("#myTextBox").caret();

于 2014-01-29T10:30:03.553 回答
7

我们曾经在一个旧的 javascript 应用程序中使用过类似的东西，但我已经有几年没有测试过了：

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;
}
于 2011-02-08T02:21:29.257 回答
1

在文本框中获取光标点的工作示例：

function textbox()
{
    var ctl = document.getElementById('Javascript_example');
    var startPos = ctl.selectionStart;
    var endPos = ctl.selectionEnd;
    alert(startPos + ", " + endPos);
}
于 2019-03-18T10:58:13.117 回答
0

获取当前插入符号位置的坐标 (css: left:x , top:y) 以定位元素（例如在插入符号位置显示工具提示）

function getCaretCoordinates() {
  let x = 0,
    y = 0;
  const isSupported = typeof window.getSelection !== "undefined";
  if (isSupported) {
    const selection = window.getSelection();
    // Check if there is a selection (i.e. cursor in place)
    if (selection.rangeCount !== 0) {
      // Clone the range
      const range = selection.getRangeAt(0).cloneRange();
      // Collapse the range to the start, so there are not multiple chars selected
      range.collapse(true);
      // getCientRects returns all the positioning information we need
      const rect = range.getClientRects()[0];
      if (rect) {
        x = rect.left; // since the caret is only 1px wide, left == right
        y = rect.top; // top edge of the caret
      }
    }
  }
  return { x, y };
}

演示：https ://codesandbox.io/s/caret-coordinates-index-contenteditable-9tq3o?from-embed

参考：https ://javascript.plainenglish.io/how-to-find-the-caret-inside-a-contenteditable-element-955a5ad9bf81

于 2022-02-23T18:14:45.473 回答