Function escHandle

static/editor.md/editormd.js:2536–2540

(event)

            codeMirror.toggle();
            
            var escHandle = function(event) {
                if (event.shiftKey && event.keyCode === 27) {
                    _this.previewed();
                }
            };

            if (codeMirror.css("display") === "none") // 为了兼容Zepto，而不使用codeMirror.is(":hidden")
            {