Javascript Contenteditable-将Cursor / Caret设置为索引

Question

我该如何修改它如何在contenteditable元素（div）中设置caret（cursor）位置？使其接受数字索引和元素，并将光标位置设置为该索引？

例如：如果我有以下段落：

<p contenteditable="true">This is a paragraph.</p>

我打电话给：

setCaret($(this).get(0), 3)

光标将移动到索引3，如下所示：

Thi|s is a paragraph.

我有这个，但是没有运气：

function setCaret(contentEditableElement, index)
{
    var range,selection;
    if(document.createRange)//Firefox, Chrome, Opera, Safari, IE 9+
    {
        range = document.createRange();//Create a range (a range is a like the selection but invisible)
        range.setStart(contentEditableElement,index);
        range.collapse(true);
        selection = window.getSelection();//get the selection object (allows you to change selection)
        selection.removeAllRanges();//remove any selections already made
        selection.addRange(range);//make the range you have just created the visible selection
    }
    else if(document.selection)//IE 8 and lower
    { 
        range = document.body.createTextRange();//Create a range (a range is a like the selection but invisible)
        range.moveToElementText(contentEditableElement);//Select the entire contents of the element with the range
        range.collapse(false);//collapse the range to the end point. false means collapse to end rather than the start
        range.select();//Select the range (make it the visible selection
    }
}

Answer 1

这是从HTML中选择后持久保留范围对象的更改而来的一个答案。请记住，这在几个方面都不是完美的（就像使用相同方法的MaxArt一样）：首先，仅考虑文本节点，这意味着<br>索引所隐含的换行符和块元素不包括在索引中；其次，考虑所有文本节点，甚至是那些被CSS隐藏的内部<script>元素或内部元素。第三，连续折叠在页面上的空白字符都包含在索引中；最后，IE<= 8的规则再次有所不同，因为它使用了不同的机制。

var setSelectionByCharacterOffsets = null;

if (window.getSelection && document.createRange) {
    setSelectionByCharacterOffsets = function(containerEl, start, end) {
        var charIndex = 0, range = document.createRange();
        range.setStart(containerEl, 0);
        range.collapse(true);
        var nodeStack = [containerEl], node, foundStart = false, stop = false;

        while (!stop && (node = nodeStack.pop())) {
            if (node.nodeType == 3) {
                var nextCharIndex = charIndex + node.length;
                if (!foundStart && start >= charIndex && start <= nextCharIndex) {
                    range.setStart(node, start - charIndex);
                    foundStart = true;
                }
                if (foundStart && end >= charIndex && end <= nextCharIndex) {
                    range.setEnd(node, end - charIndex);
                    stop = true;
                }
                charIndex = nextCharIndex;
            } else {
                var i = node.childNodes.length;
                while (i--) {
                    nodeStack.push(node.childNodes[i]);
                }
            }
        }

        var sel = window.getSelection();
        sel.removeAllRanges();
        sel.addRange(range);
    }
} else if (document.selection) {
    setSelectionByCharacterOffsets = function(containerEl, start, end) {
        var textRange = document.body.createTextRange();
        textRange.moveToElementText(containerEl);
        textRange.collapse(true);
        textRange.moveEnd("character", end);
        textRange.moveStart("character", start);
        textRange.select();
    };
}