实现HTML编辑器的第1步就是在网页中放置一个可编辑的iframe用来输入文本,使iframe可编辑方法相当简单,只需要将iframe的designMode设置为on即可,具体步骤如下:
var editor = document.getElementById("IFRAME的ID"); var editorDoc = editor.contentWindow.document; var editorWindow = editor.contentWindow; editorDoc.designMode = "on"; editorDoc.open(); editorDoc.write("<html><head></head><body style='margin:0px; padding: 0px;'></body></html>"); editorDoc.close();
设置选中文本样式的方法最简单的方式就是使用document.execCommand,但是execCommand功能比较局限,有时不能满足需求,例如:execCommand设置字体大小只能是1-7,不能使用像素大小,而且如果你在点击工具栏按钮到调用execCommand的过程中点击了其他的DIV,iframe的选中内容会消失,这时调用execCommand是无效的。因此本文介绍另一种方法,基本思路如下
(1) 获取选中的HTML;
(2) 修改HTML的样式;
(3) 用修改后的HTML替换选中的HTML。
在不同的浏览器中获取选中的HTML的方法是不同的
var range = document.selection.createRange();//IE var range = window.getSelection().getRangeAt(0);//FireFox、Chrome
通过2.1的方法获取了表示选中内容的对象后,就可以调用其方法来替换掉选中的内容。在不同的浏览器中替换选中的HTML的方法有所差异,在IE中可以只需调用range.pasteHTML就行了,在Firefox,Chrome中则使用range.deleteContents 和 range.insertNode 两个方法来实现
由于2.1中获取的range对象的方法在不同浏览器中差异很大,因此,为了方便实现2.1和2.2提到的两个操作,封装了一个操作选中HTML的类SelectionRange,该类有两个方法,GetSelectedHtml和Replace,分别用于获取HTML和替换HTML。其代码如下:
//用于记录浏览器的类型 var browser = {}; var ua = navigator.userAgent.toLowerCase(); browser.msie = (/msie ([\d.]+)/).test(ua); browser.firefox = (/firefox\/([\d.]+)/).test(ua); browser.chrome = (/chrome\/([\d.]+)/).test(ua); //获取多个节点的HTML function GetInnerHTML(nodes) { var builder = []; for (var i = 0; i < nodes.length; i++) { if (nodes[i].nodeValue != undefined) { builder.push(nodes[i].innerHTML); } else { if (nodes[i].textContent) builder.push(nodes[i].textContent.replace(/\</ig, function() { return "<"; })); else if (nodes[i].nodeValue) builder.push(nodes[i].nodeValue.replace(/\</ig, function() { return "<"; })); } } return builder.join(""); } function SelectionRange(doc, range) { //获取选中的内容的HTML this.GetSelectedHtml = function() { if (range == null) return ""; if (browser.msie) { if (range.htmlText != undefined) return range.htmlText; else return ""; } else if (browser.firefox || browser.chrome) { return GetInnerHTML(range.cloneContents().childNodes); } else { return ""; } } //用html替换选中的内容的HTML this.Replace = function(html) { if (range != null) { if (browser.msie) { if (range.pasteHTML != undefined) { //当前选中html可能以为某种原因(例如点击了另一个DIV)而丢失,重新选中 range.select(); range.pasteHTML(html); return true; } } else if (browser.firefox || browser.chrome) { if (range.deleteContents != undefined && range.insertNode != undefined) { //将文本html转换成DOM对象 var temp = doc.createElement("DIV"); temp.innerHTML = html; var elems = []; for (var i = 0; i < temp.childNodes.length; i++) { elems.push(temp.childNodes[i]); } //删除选中的节点 range.deleteContents(); //将html对应的节点(即temp的所有子节点)逐个插入到range中,并从temp中删除 for (var i in elems) { temp.removeChild(elems[i]); range.insertNode(elems[i]); } return true; } } } return false; } }
与此同时,还实现了一个函数GetSelectionRange用于获取当前选中文本对应的SelectionRange对象,
function GetSelectionRange(win) { var range = null; if (browser.msie) { range = win.document.selection.createRange(); if (range.parentElement().document != win.document) { range = null; } } else if (browser.firefox || browser.chrome) { var sel = win.getSelection(); if (sel.rangeCount > 0) range = sel.getRangeAt(0); else range = null; } return new SelectionRange(win.document, range); }
修改选中的HTML的样式方法并不复杂,只需要将HTML转成DOM对象,然后递归的设置每一个节点对应的样式的值即可,具体代码如下:
function SetNodeStyle(doc, node, name, value) { if (node.innerHTML == undefined) { return node; } else { node.style[name] = value; for (var i = 0; i < node.childNodes.length; i++) { var cn = node.childNodes[i]; if (node.innerHTML != undefined) { SetNodeStyle(doc, cn, name, value); } } return node; } } function SetStyle(doc, html, name, value) { var dom = doc.createElement("DIV"); dom.innerHTML = html; for (var i = 0; i < dom.childNodes.length; i++) { var node = dom.childNodes[i]; if (node.innerHTML == undefined) { //如果是文本节点,则转换转换成span var span = doc.createElement("SPAN"); span.style[name] = value; if (node.nodeValue != undefined) span.innerHTML = node.nodeValue.replace(/\</ig, function() { return "<"; }); else if (node.textContent != undefined) span.innetHTML = node.textContent.replace(/\</ig, function() { return "<"; }); //替换掉文本节点 dom.replaceChild(span, node); } else { SetNodeStyle(doc, node, name, value); } } return dom.innerHTML; }
使用以上的代码,就可以相当方便的实现一个HTML编辑器,例如,以下代码实现将选中文本的字体大小设置为32px:
var range = GetSelectionRange(editorWindow); var html = SetStyle(editorDoc, range.GetSelectedHtml(), "fontSize", "32px"); range.Replace(html);
同理,你可以实现设置行距,缩进,插入图片等功能。
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Untitled Page</title> <script type="text/javascript" language="javascript"> //判断浏览器 var browser = {}; var ua = navigator.userAgent.toLowerCase(); browser.msie = (/msie ([\d.]+)/).test(ua); browser.firefox = (/firefox\/([\d.]+)/).test(ua); browser.chrome = (/chrome\/([\d.]+)/).test(ua); function SetNodeStyle(doc, node, name, value) { if (node.innerHTML == undefined) { return node; } else { node.style[name] = value; for (var i = 0; i < node.childNodes.length; i++) { var cn = node.childNodes[i]; if (node.innerHTML != undefined) { SetNodeStyle(doc, cn, name, value); } } return node; } } function SetStyle(doc, html, name, value) { var dom = doc.createElement("DIV"); dom.innerHTML = html; for (var i = 0; i < dom.childNodes.length; i++) { var node = dom.childNodes[i]; if (node.innerHTML == undefined) { var span = doc.createElement("SPAN"); span.style[name] = value; if (node.nodeValue != undefined) span.innerHTML = node.nodeValue.replace(/\</ig, function() { return "<"; }); else if (node.textContent != undefined) span.innetHTML = node.textContent.replace(/\</ig, function() { return "<"; }); dom.replaceChild(span, node); } else { SetNodeStyle(doc, node, name, value); } } return dom.innerHTML; } function GetInnerHTML(nodes) { var builder = []; for (var i = 0; i < nodes.length; i++) { if (nodes[i].innerHTML != undefined) { builder.push(nodes[i].innerHTML); } else { if (nodes[i].textContent) builder.push(nodes[i].textContent.replace(/\</ig, function() { return "<"; })); else if (nodes[i].nodeValue) builder.push(nodes[i].nodeValue.replace(/\</ig, function() { return "<"; })); } } return builder.join(""); } function SelectionRange(doc, range) { this.GetSelectedHtml = function() { if (range == null) return ""; if (browser.msie) { if (range.htmlText != undefined) return range.htmlText; else return ""; } else if (browser.firefox || browser.chrome) { return GetInnerHTML(range.cloneContents().childNodes); } else { return ""; } } this.Replace = function(html) { if (range != null) { if (browser.msie) { if (range.pasteHTML != undefined) { range.select(); range.pasteHTML(html); return true; } } else if (browser.firefox || browser.chrome) { if (range.deleteContents != undefined && range.insertNode != undefined) { var temp = doc.createElement("DIV"); temp.innerHTML = html; var elems = []; for (var i = 0; i < temp.childNodes.length; i++) { elems.push(temp.childNodes[i]); } range.deleteContents(); for (var i in elems) { temp.removeChild(elems[i]); range.insertNode(elems[i]); } return true; } } } return false; } } function GetSelectionRange(win) { var range = null; if (browser.msie) { range = win.document.selection.createRange(); if (range.parentElement().document != win.document) { range = null; } } else if (browser.firefox || browser.chrome) { var sel = win.getSelection(); if (sel.rangeCount > 0) range = sel.getRangeAt(0); else range = null; } return new SelectionRange(win.document, range); } function RichEditor(container, width, height) { container.innerHTML = '<div style="margin: 0px; padding: 0px; background-color: #DDDDDD;">' + '<img alt="" unselectable="on" src="image/img.gif" style="float: left; cursor:pointer; -moz-user-select:-moz-none; -webkit-user-select:none;" />' + '<img alt="" unselectable="on" src="image/b.gif" style="float: left; cursor:pointer; -moz-user-select:-moz-none; -webkit-user-select:none;" />' + '<img alt="" unselectable="on" src="image/u.gif" style="float: left; cursor:pointer; -moz-user-select:-moz-none; -webkit-user-select:none;" />' + '<img alt="" unselectable="on" src="image/i.gif" style="float: left; cursor:pointer; -moz-user-select:-moz-none; -webkit-user-select:none;" />' + '<span style="font-size:12px; margin:6px; float: left;">大小</span>' + '<select style="width: 70px; margin-left:4px; margin-top: 2px; float: left;">' + '<option value="12px">12</option>' + '<option value="14px">14</option>' + '<option value="16px">16</option>' + '<option value="18px">18</option>' + '<option value="20px">20</option>' + '<option value="22px">22</option>' + '<option value="24px">24</option>' + '<option value="36px">36</option>' + '<option value="48px">48</option>' + '<option value="72px">72</option>' + '</select>' + '<span style="font-size:12px; margin:6px; float: left;">字体</span>' + '<select style="width: 150px; margin-left:4px; margin-top: 2px; float: left;">' + '<option value="宋体">宋体</option>' + '<option value="Times New Roman">Times New Roman</option>' + '<option value="Courier New">Courier New</option>' + '<option value="Verdana">Verdana</option>' + '</select>' + '</div>' + '<iframe frameborder="0" style="padding: 0px;"></iframe>'; var toolbar = container.childNodes[0]; var editor = container.childNodes[1]; var editorDoc = editor.contentWindow.document; var editorWindow = editor.contentWindow; toolbar.style.width = width + 'px'; toolbar.style.height = '24px'; editor.style.width = width + 'px'; editor.style.height = (height - 24) + 'px'; if (browser.firefox) { editor.onload = function() { editorDoc.designMode = "on"; } } else { editorDoc.designMode = "on"; } editorDoc.open(); editorDoc.write("<html><head></head><body style='margin:0px; padding: 0px;'></body></html>"); editorDoc.close(); toolbar.childNodes[0].onclick = function() { var src = prompt("请输入图片的URL:", ""); if (src != null) { var range = GetSelectionRange(editorWindow); range.Replace("<img src='" + src + "'></img>"); } } toolbar.childNodes[1].onclick = function() { editorDoc.execCommand("Bold", false, null); } toolbar.childNodes[2].onclick = function() { editorDoc.execCommand("Underline", false, null); } toolbar.childNodes[3].onclick = function() { editorDoc.execCommand("Italic", false, null); } toolbar.childNodes[5].onchange = function() { var range = GetSelectionRange(editorWindow); var html = SetStyle(editorDoc, range.GetSelectedHtml(), "fontSize", toolbar.childNodes[5].value); range.Replace(html); } toolbar.childNodes[7].onchange = function() { var range = GetSelectionRange(editorWindow); var html = SetStyle(editorDoc, range.GetSelectedHtml(), "fontFamily", toolbar.childNodes[7].value); range.Replace(html); } } window.onload = function() { var editor = new RichEditor(document.getElementById("richEditor"), 600, 250); } </script> </head> <body> <div id="richEditor" style="width: 600px; border: 1px solid #000000;"> </div> </body> </html>