isNaN()是JavaScript裡的函式,可判斷非為數字 document.write(isNaN(123)); document.write(isNaN(-3)); document.write(isNaN(0.3)); document.write(isNaN(0)); document.write(isNaN(5/16)); document.write(isNaN("A")); 結果為 false false false false false true 至於nl2br()則是PHP的函式,可以把像\n之類的換行字元轉成<br> <?php $String="Hello, This is C.C.\nCan you hear me?"; echo nl2br($String); ?> 結果 Hello, This is C.C. Can you hear me?