Javascript 正規表達式

常常用到正規表達式
所以記錄一下在 Javascript 中的用法

<script language="javascript">
   var str = "46 Ladys and Gentleman~\nWelcome 12 to the show !";
   document.write("Test string : <br>" + str.replace("\n","<br>") + "<br><br>");
 
   var RegStr_NoGlobal = /\d/;
   /* 使用g(Global)參數時，RegExp在做test()或exec()時 */
   /* 會保存一個指標lastIndex，記錄上次查詢結束的位置。 */
   /* 第一次test()後，lastIndex就指向字串結尾 */
   /* 第二次test()由結尾開始查，啥都查不到，就傳回false，*/
   /* 然後再把lastIndex重設為0。 */
   var RegStr_Global = /\d/g;
   var RegStr_NoIgnoreCase = /wel/;
   var RegStr_IgnoreCase = /wel/i;
   var RegStr_NoMultiLine = /^Wel/;
   var RegStr_MultiLine = /^Wel/m;
   var RegStr_Variable = /[a-z]+([a-z]{2}) /gi;
 
   var result;
 
   result = RegStr_NoGlobal.exec(str);
   document.write("No-Global Round1 : " + result + "<br>");
   result = RegStr_NoGlobal.exec(str);
   document.write("No-Global Round2 : " + result + "<br>");
 
   result = RegStr_Global.exec(str);
   document.write ("Global Round1 : " + result + "<br>");
   result = RegStr_Global.exec(str);
   document.write ("Global Round2 : " + result + "<br><br>");
 
   result = RegStr_NoIgnoreCase.exec(str);
   document.write("No-IgnoreCase : " + result + "<br>");
 
   result = RegStr_IgnoreCase.exec(str);
   document.write("IgnoreCase : " + result + "<br><br>");
 
   result = RegStr_NoMultiLine.exec(str);
   document.write("No-MultiLine : " + result + "<br>");
 
   result = RegStr_MultiLine.exec(str);
   document.write("MultiLine : " + result + "<br><br>");
 
   result = RegStr_Variable.exec(str);
   document.write("Match string : " + result[0] + " , Match variable : " + result[1] + "<br>");
   result = RegStr_Variable.exec(str);
   document.write("Match string : " + result[0] + " , Match variable : " + result[1] + "<br>");
   result = RegStr_Variable.exec(str);
   document.write("Match string : " + result[0] + " , Match variable : " + result[1] + "<br>");
   result = RegStr_Variable.exec(str);
   document.write("Match string : " + result[0] + " , Match variable : " + result[1] + "<br>");
   result = RegStr_Variable.exec(str);
   document.write("Match string : " + result[0] + " , Match variable : " + result[1] + "<br>");
</script>