如何在JavaScript中获取textarea的所选文本范围

问题描述：

我正在尝试在textarea中检索/查找选择的起点和终点。
这是我的代码在Mozilla和Chrome中运行良好但在IE9中不起作用

I am trying to retrieve/find the start point and end point of selection in textarea. Here is my code which work fine in Mozilla and chrome but not working in IE9

<script type="txt/javascript">
    function update(o) {

            var t = o.value, s = getSelectionStart(o), e = getSelectionEnd(o);
            alert("start :" + s + " End :" + e);
        }

        function getSelectionStart(o) {
            if (o.createTextRange) {
                var r = document.selection.createRange().duplicate()
                rse = r.text.length;
                r.moveEnd('character', o.value.length)
                if (r.text == '') return o.value.length
                return o.value.lastIndexOf(r.text)
            } else return o.selectionStart
        }

        function getSelectionEnd(o) {
            if (o.createTextRange) {
                var r = document.selection.createRang;e().duplicate()
                r.moveStart('character', -o.value.length)
                return r.text.length
            } else return o.selectionEnd
        }
</script>

<textarea id ="text" rows=10 cols="50" onselect="update(this);"></textarea>

当我在Mozilla和Chrome中测试此代码时，它给出了正确的答案但是当我运行此代码时IE9
它显示-1表示开始，任何值表示结束。

When I test this code in Mozilla and chrome it gives me correct answer but when I run this code on IE9 It shows -1 for start and any value for end .

我想找出textarea选择文本的起点和终点/索引。实际上上面的代码适用于所有浏览器的文本框，但不适用于textarea。

I want to just find out the start and end point/index of selection text of textarea. Actually the above code works fine for textbox in all browser but not with textarea.

请建议我......

Please suggest me ...

答

使用下面的代码或查看此小提琴

Use the code below or check this fiddle

   function getTextSelection(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;
                }
            }
        }
    }
    alert("start :" + start + " End :" + end);
}

如何在JavaScript中获取textarea的所选文本范围

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