this.settings.upload_url = SWFUpload.completeURL(this.settings.upload_url);this.settings.button_image_url = SWFUpload.completeURL(this.settings.button_image_url)

改为

this.settings.upload_url = SWFUpload.completeURL(this.settings.upload_url);this.settings.button_image_url = this.settings.button_image_url ? SWFUpload.completeURL(this.settings.button_image_url) : this.settings.button_image_url

jquery uploadify 进入页面请求两次问题解决办法。