原因:execCommand(`insertHTML`) IE11 不相容
解決方法:
var range = I.window.$.getSelection().getRangeAt(0);
range.deleteContents();
range = range.cloneRange();
var node_span = document.createElement(`span`);
$(node_span).append(C);
var new_node=range.createContextualFragment($(node_span).prop(`outerHTML`));
range.insertNode( new_node );