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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html> <head> <title> New Document </title> <meta name="Generator" content="EditPlus"> <meta name="Author" content=""> <meta name="Keywords" content=""> <meta name="Description" content=""> <script type="text/javascript">/*五種基礎資料型別 (Elementary Data Type)：number:數值string:字串boolean:布爾null：空undefined:未定義引用資料類型：typeof資料類型轉換Number()、parseInt()和parseFloat()Boolean()轉換規則以下值為false： null undefined Null 字元串"" 數值0 為null的對象 */<!--輸出值的類型-->var width;var arrlist=new Date();document.write(typeof("woanji")+"<br />"); //結果為stringdocument.write(typeof(12)+"<br />"); //結果為numberdocument.write(typeof(true)+"<br />"); //結果為booleandocument.write(typeof(null)+"<br />"); //結果為objectdocument.write(typeof(arrlist)+"<br />"); //結果為objectdocument.write(typeof(width)+"<br />"); //結果為undefinedfunction test(a,b){alert("sum:"+(a+b));}//判斷值或函數是否為某類型的對象，返回boolean類型document.write(test instanceof Object);//結果為true，說明函數本質是也是對象var sss = "123sdfg";document.write(sss instanceof String); //結果為false，說明sss不是string的對象 </script> </head> <body> </body></html>
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