Javascript Contenteditable - 将Cursor / Caret设置为索引

时间:2013-04-19 00:12:12

标签: javascript jquery contenteditable

我如何修改这个(How to set caret(cursor) position in contenteditable element (div)?)以便接受数字索引和元素并将光标位置设置为该索引?

例如: 如果我有段落:

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

我打来电话:

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
    }
}

http://jsfiddle.net/BanQU/4/

3 个答案:

答案 0 :(得分:9)

这是一个改编自Persisting the changes of range objects after selection in HTML的答案。请记住,这在几个方面并不完美(正如MaxArt的,使用相同的方法):首先,只考虑文本节点,这意味着<br>隐含的换行符和块元素不是包括在索引中;其次,考虑所有文本节点,甚至是那些被CSS或<script>元素内部隐藏的元素内部;第三,页面上折叠的连续空白字符都包含在索引中;最后,IE&lt; = 8的规则再次不同,因为它使用不同的机制。

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();
    };
}

答案 1 :(得分:7)

range.setStartrange.setEnd可用于 text 节点,而非元素节点。否则他们会引发DOM异常。所以你需要做的是

range.setStart(contentEditableElement.firstChild, index);

我不知道你为IE8做了什么,并且降低了。你在哪里使用index

总的来说,如果节点的内容超过单个文本节点,则代码将失败。具有isContentEditable === true的节点可能会发生这种情况,因为用户可以从Word或其他位置粘贴文本,或者创建新行等等。

以下是我在框架中所做的改编:

var setSelectionRange = function(element, start, end) {
    var rng = document.createRange(),
        sel = getSelection(),
        n, o = 0,
        tw = document.createTreeWalker(element, NodeFilter.SHOW_TEXT, null, null);
    while (n = tw.nextNode()) {
        o += n.nodeValue.length;
        if (o > start) {
            rng.setStart(n, n.nodeValue.length + start - o);
            start = Infinity;
        }
        if (o >= end) {
            rng.setEnd(n, n.nodeValue.length + end - o);
            break;
        }
    }
    sel.removeAllRanges();
    sel.addRange(rng);
};

var setCaret = function(element, index) {
    setSelectionRange(element, index, index);
};

这里的诀窍是使用setSelectionRange函数 - 用start === end选择里面的文本范围和元素。在contentEditable元素中,这会将插入符号置于所需位置。

这适用于所有现代浏览器,以及不仅仅包含文本节点作为后代的元素。我会允许您将startend的检查添加到适当的范围内。

对于IE8及更低版本,事情有点困难。事情看起来有点像这样:

var setSelectionRange = function(element, start, end) {
    var rng = document.body.createTextRange();
    rng.moveToElementText(element);
    rng.moveStart("character", start);
    rng.moveEnd("character", end - element.innerText.length - 1);
    rng.select();
};

这里的问题是innerText 不适合这种事情,因为有些空格会崩溃。如果只有一个文本节点,那就很好了,但是对于像contentEditable元素中的那些更复杂的东西,这些东西都很复杂。

IE8不支持textContent,因此您必须使用TreeWalker计算字符数。但IE8也不支持TreeWalker,所以你必须自己走DOM树...

我仍然需要解决这个问题,但不知怎的,我怀疑自己永远不会。即使我 在IE8中为TreeWalker代码填充以及更低......

答案 2 :(得分:2)

这是我对蒂姆答案的改进。它删除了关于隐藏字符的警告,但其他警告仍然存在:

  • 仅考虑文本节点(&lt; br&gt;隐含的换行符和索引元素不包含在索引中)
  • 考虑所有文本节点,甚至是那些被CSS或内部元素隐藏的元素内部
  • IE&lt; = 8&quot;规则再次不同,因为它使用不同的机制。

代码:

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 hiddenCharacters = findHiddenCharacters(node, node.length)
                var nextCharIndex = charIndex + node.length - hiddenCharacters;

                if (!foundStart && start >= charIndex && start <= nextCharIndex) {
                    var nodeIndex = start-charIndex
                    var hiddenCharactersBeforeStart = findHiddenCharacters(node, nodeIndex)
                    range.setStart(node, nodeIndex + hiddenCharactersBeforeStart);
                    foundStart = true;
                }
                if (foundStart && end >= charIndex && end <= nextCharIndex) {
                    var nodeIndex = end-charIndex
                    var hiddenCharactersBeforeEnd = findHiddenCharacters(node, nodeIndex)
                    range.setEnd(node, nodeIndex + hiddenCharactersBeforeEnd);
                    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();
    };
}

var x = document.getElementById('a')
x.focus()
setSelectionByCharacterOffsets(x, 1, 13)

function findHiddenCharacters(node, beforeCaretIndex) {
    var hiddenCharacters = 0
    var lastCharWasWhiteSpace=true
    for(var n=0; n-hiddenCharacters<beforeCaretIndex &&n<node.length; n++) {
        if([' ','\n','\t','\r'].indexOf(node.textContent[n]) !== -1) {
            if(lastCharWasWhiteSpace)
                hiddenCharacters++
            else
                lastCharWasWhiteSpace = true
        } else {
            lastCharWasWhiteSpace = false   
        }
    }

    return hiddenCharacters
}