textarea 根据光标位置添加内容
// 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); }