// 获取焦点      let txt = document.getElementById("countRule");      let temp = txt.value;      txt.focus();      let pointIndex = txt.selectionStart;      let str1 = temp.substr(0,pointIndex);      let str2 = temp.substr(pointIndex,temp.length);      txt.value = str1+dom+str2;      if( site != 'no' ){        let newIndex = pointIndex + site;        txt.setSelectionRange(newIndex,newIndex);      }