原文:http://www.jb51.net/article/57650.htm
<html>
<body>
<button type="button" onclick="document.getElementById(‘test‘).focus(); insertHtmlAtCaret(‘<b>INSERTED</b>‘);">插入字符</button>
<div contentEditable="true" style="height:50px; border:2px solid red;" id="test"> </div>
</body>
<script>
function insertHtmlAtCaret(html) {
var sel, range;
if (window.getSelection) {
// IE9 and non-IE
sel = window.getSelection();
if (sel.getRangeAt && sel.rangeCount) {
range = sel.getRangeAt(0);
range.deleteContents();
// Range.createContextualFragment() would be useful here but is
// non-standard and not supported in all browsers (IE9, for one)
var el = document.createElement("div");
el.innerHTML = html;
var frag = document.createDocumentFragment(), node, lastNode;
while ( (node = el.firstChild) ) {
lastNode = frag.appendChild(node);
}
range.insertNode(frag);
// Preserve the selection
if (lastNode) {
range = range.cloneRange();
range.setStartAfter(lastNode);
range.collapse(true);
sel.removeAllRanges();
sel.addRange(range);
}
}
} else if (document.selection && document.selection.type != "Control") {
// IE < 9
document.selection.createRange().pasteHTML(html);
}
}
</script>
<html>
原文：http://www.cnblogs.com/zxy562323273/p/4588984.html