如何檢查，選中的文字是否加粗（contenteditable）

Question

我正在使用 html 內置的contenteditable功能實現自定義文本編輯器。 我需要知道用戶何時在文本編輯器上選擇了文本是否為粗體。

這是我現在所擁有的：

HTML

<button onclick="boldit()">B</button>
<div id="editor" contenteditable="true" class="email-body">
    This is an <strong>editable</strong> paragraph.
</div>

Javascript

function boldit(){
 document.execCommand('bold');
}

Answer 1

可靠的方法是遍歷父樹檢查getComputedStyle。

我假設您已經擁有選定的元素。

function isBold(_element) {
  var element = _element;
  while (element) {
    var style = getComputedStyle(element).fontWeight;
    if (Number(fontWeight) > 400 || fontWeight === 'bold' || fontWeight === 'bolder') {
      return true;
    }
    element = element.parentNode;
  }
  return false;
}

Answer 2

 jQuery(function($) { $('.embolden').click(function(){ if(selectionIsBold()){ alert('bold'); } else { alert('not bold'); } }); }); function selectionIsBold() { var isBold = false; if (document.queryCommandState) { isBold = document.queryCommandState("bold"); } return isBold; }

 .bold { font-weight: bold; }

 <div contenteditable="true" class="textEditor">Some <span class="bold">random </span>text.</div> <a href="#" class="embolden">Is Bold Text</a> <script src="https://code.jquery.com/jquery-3.2.1.min.js" integrity="sha256-hwg4gsxgFZhOsEEamdOYGBf13FyQuiTwlAQgxVSNgt4=" crossorigin="anonymous"></script>

突出顯示文本並單擊鏈接。

Answer 3

只需調用isSelectionBold() :)

CodePen 上的演示

function isSelectionBold() {
  var sel;
  if (window.getSelection) { 
    sel = window.getSelection(); 
  } 
  else if (document.getSelection) { 
    sel = document.getSelection(); 
  }
  
    var raw_html = getSelectionAsHtml();
  
  // This is if nothing is selected
  if(raw_html==="") return false;

  var tempDiv = document.createElement('div');
  tempDiv.innerHTML = raw_html;
    
  var is_bold_nodes = []
    for (var node of tempDiv.childNodes) {
    var tags = [node.nodeName.toLowerCase()];
        
    // This covers selection that are inside bolded characters
    while(tags.includes("#text")) {
      var start_tag = sel.anchorNode.parentNode.nodeName.toLowerCase();
      var end_tag = sel.focusNode.parentNode.nodeName.toLowerCase();
      
            tags = [start_tag, end_tag]
    }

        is_bold_nodes.push(containsOnly(['strong', 'b'], tags));
    }
    
    return (! is_bold_nodes.includes(false))
}

function getSelectionAsHtml() {
    var html = "";
    if (typeof window.getSelection != "undefined") {
        var sel = window.getSelection();
        if (sel.rangeCount) {
            var container = document.createElement("div");
            for (var i = 0, len = sel.rangeCount; i < len; ++i) {
                container.appendChild(sel.getRangeAt(i).cloneContents());
            }
            html = container.innerHTML;
        }
    } else if (typeof document.selection != "undefined") {
        if (document.selection.type == "Text") {
            html = document.selection.createRange().htmlText;
        }
    }
    return html;
}

function containsOnly(array1, array2){
  return !array2.some(elem => !array1.includes(elem))
}