javascript - 如何获取选定的文本范围并向特定选定的文本添加颜色

Question

我遇到了一个问题，我有这样的描述性原始文本 -

<p>I am using the following code to change the color of text but it is not working.. Can anyone help me with this? the soloution in javascript or jquery anything is fine..</p> 

现在我的要求是

• 在鼠标按下事件时查找特定选定文本的位置(范围)
• 在整个操作过程中对所选文本进行着色

我写的代码

    $(document).ready(function() {
            if (!window.Wafer) {
                Wafer = {};
            }
            Wafer.Selector = {};

            /* Function to get selected string as a object
             *  works for all browser and also handle for old browser like
             * ie9,firfox 18 as discussed
             */
            Wafer.Selector.getSelected = function() {

                $selObj = '';
                if (window.getSelection) {
                    $selObj = window.getSelection();
                } else if (document.getSelection) {
                    $selObj = document.getSelection();
                } else if (document.selection) {
                    $selObj = document.selection.createRange().text;
                }
                //console.log($selObj);
                return $selObj;
            }
            //holding the selector string in variable on mouseup event
            Wafer.Selector.mouseup = function() {
                $selector = Wafer.Selector.getSelected();
                $start = $selector.anchorOffset;
                $end = $selector.focusOffset;
                console.log($start, $end);
                //I call this to wrap selected text under span 
                selectText('#f90');
            }
            //This will tell jquery to fire when "mouseup" event will occur
            $(document).on("mouseup", Wafer.Selector.mouseup);
        });

        function selectText(hexColor) {
            var selection = window.getSelection().getRangeAt(0);
            var selectedText = selection.extractContents();
            var span = document.createElement('span');
            span.style.backgroundColor = hexColor;
            span.className = 'selected-text';
            span.appendChild(selectedText);
            selection.insertNode(span);
        }

在函数selectText中，我曾经得到window.getSelection().getRangeAt(0);，这可能与window.getSelection()冲突> 并且两者都返回具有 anchoroffset 和 focusoffset 键的对象，因此无法获得正确的文本范围

有什么方法可以清除选定的文本范围吗？

关注了几个堆栈帖子，例如 this但这些部分满足了我的要求并且有错误的代码。提前致谢。

Answer 1

有这个问题的人可以通过这种方式获得帮助-

$("#text-box").mouseup(function () {
    var el = document.getElementById("text-box");
    getCaretCharacterOffsetWithin(el);
});

每次从父容器获取选择并查找开始和结束范围的函数。

 function getCaretCharacterOffsetWithin(element) {
    var caretOffset = 0;
    var doc = element.ownerDocument || element.document;
    var win = doc.defaultView || doc.parentWindow;
    var sel;
    if (typeof win.getSelection != "undefined") {
        sel = win.getSelection();
        if (sel.rangeCount > 0) {
            var range = win.getSelection().getRangeAt(0);
            var preCaretRange = range.cloneRange();
            preCaretRange.selectNodeContents(element);
            preCaretRange.setEnd(range.endContainer, range.endOffset);
            caretOffset = preCaretRange.toString().length;
        }
    } else if ((sel = doc.selection) && sel.type != "Control") {
        var textRange = sel.createRange();
        var preCaretTextRange = doc.body.createTextRange();
        preCaretTextRange.moveToElementText(element);
        preCaretTextRange.setEndPoint("EndToEnd", textRange);
        caretOffset = preCaretTextRange.text.length;
    }
    var start = caretOffset - sel.toString().length;
    var end = caretOffset - 1;
    if (start != end && end > start) {
        // Highlight the text
        console.log(start,end);
        var selectedText = range.extractContents();
        var text_value = selectedText.textContent;
        var span = document.createElement('span');
        span.style.backgroundColor = "red";
        span.className = 'selected-text';
        span.appendChild(selectedText);
        range.insertNode(span);
        $(".span").html(start + ", " + end);
        return caretOffset;
    }
}

你的 HTML 可能是这样的

<div id="text-box" style="width: 700px; border:1px solid black">Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book. It has survived not only five centuries, but also the leap into electronic typesetting, remaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages, and more recently with desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum</div>

我还添加了 span 标签来包装在 mouseup 事件上选择的范围文本，因为我需要添加颜色 到被选择的字段。希望这会有所帮助。 :-)