var newsname; 
 ctrl.checkNameLegal = function () {
 if (ctrl.fileName) {
var exports = /^(?![.])[\u4e00-\u9fa5_.a-zA-Z0-9]+$/ig;
if (exports.test(ctrl.fileName)) {
  newsname = ctrl.fileName;
} else {
  ctrl.fileName = newsname;
}} else {
newsname = "";} 
}; 
 this is written in an abnormal way. Is there any way to replace it with 
 ctrl.fileName = ctrl.fileName.replace (/.. / ig,""); 
Thank you, God!
