SOURCE

var re=null,i;
for(i=0;i<10;i++){
  re=/cat/g;
  if(re.test("catcapppp")){
    alert("mmm");
  };
};
for(i=0;i<10;i++){
  re=new RegExp("cat","g");
  if(re.test("catcapppp")){
    alert("dddd");
  };
}