javascript - 是否有 Internet Explorer 认可的 selectionStart 和 selectionEnd 替代品？

Question

找出在真实浏览器中选择的内容很简单:

var range = {
  start: textbox.selectionStart,
  end: textbox.selectionEnd
}

但是 IE 像往常一样不理解。执行此操作的最佳跨浏览器方法是什么？

Answer 1

我将再次发布此功能，因为这个问题与另一个问题相关联。

以下将在所有浏览器中完成这项工作，并在不严重影响性能的情况下处理所有新行问题。我是在 some toing and froing 之后到达这里的现在我非常确信这是最好的此类功能。

更新

这个函数假设 textarea/input 有焦点，所以你可能需要调用 textarea 的 focus()调用之前的方法。

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 el = document.getElementById("your_input");
el.focus();
var sel = getInputSelection(el);
alert(sel.start + ", " + sel.end);