var character = 'sd13564349471中';//字符 //1.判斷該字符串里是否包含數字 function getNum(text){ var value = text.replace(/[^0-9]/ig,""); return value; } //2.if包含數字,判斷數據長度是否為11 if(getNum(character).length == 11){ //3.截取所有數字,並用*替換4,4 var phNum = getNum(character), phnumAfter = phNum.substr(0,3) + "****" + phNum.substr(7); } //4.替換輸出 var result = character.replace(phNum,phnumAfter); console.log(result)//結果 為sd135****9471中