A question about RichTextEditor, need your help!

[adoin]

Here is my code:
this.editor = isc.RichTextEditor.create({ // minHeight:400, height: 400, width: "100%", height: "100%", // overflow:"hidden", // layoutLeftMargin :100, // layoutRightMargin:100, // canDragResize:true, controlGroups: ["fontControls", "formatControls", "styleControls", "colorControls", "bulletControls"], value: "", draw:function (){ this.Super("draw",arguments); this.fontSelector.setValues({fontname:'FangSong'}) this.fontSelector.fireSelectionUpdated() this.fontSizeSelector.setValues({fontsize: "5"}) } }) And which I customize in "ISC_RichTextEditor.js":
isc.A.fontNames = { "arial,helvetica,sans-serif": "Arial", 'courier new,courier,monospace': "Courier New", 'georgia,times new roman,times,serif': "Georgia", 'tahoma,arial,helvetica,sans-serif': "Tahoma", 'times new roman,times,serif': "Times New Roman", 'verdana,arial,helvetica,sans-serif': "Verdana", "impact": "Impact", "FangSong": "仿宋", "LiSu": "隶书", "SimHei": "黑体", "SimSun": "宋体", "KaiTi": "楷体", };
I tried to set the font FangSong as default, it looks good in page: But , it in fact not really work, just seems like works. when I type any words, it still not the font I want as default. What should I do to fix it? Or how can I implement to set an default font and font size?