topical media & game development

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basic-regex-19-CreditCard.htm / htm



  <html>
  <head>
  <title>Processing a 16 digit credit card number.</title>
  <script language="ecmascript" >
  var myRegExp = /\d{4}\s\d{4}\s\d{4}\s\d{4}/;
  // \d{4} match four numeric digits
  // \s match a whitespace character
  // \d{4} match four numeric digits
  // \s match a whitespace character
  // \d{4] match four numeric digits
  // \s match a whitespace character
  // \d{4} match four numeric digits
  
  var entry;
  
  function Validate(){
  entry = document.simpleForm.CCNBox.value;
  if (myRegExp.test(entry)) {
  alert("The value you entered, " + entry + "\nmatches the regular expression, " + myRegExp + ". \nIt is a valid 16 digit credit card number." );
  } // end of the if statement
  else
  {
  alert("The value you entered," + entry + ",\nis not a valid 16 digit credit card number. Please try again.");
  } // end of else clause
  } // end Validate() function
  
  function ClearBox(){
  document.simpleForm.CCNBox.value = "";
  // The above line clears the texbox when it receives focus
  } // end ClearBox() function
  </script>
  </head>
  <body>
  <form name="simpleForm" >
  <table>
  <tr>
  <td width="50%">Enter a valid 16 digit credit card number here, separating the groups of four numbers by spaces:</td>
  <td width="40%"><input name="CCNBox" width="50" onfocus="ClearBox()" type="text" value="Enter a credit card number here"></input></td>
  </tr>
  <tr>
  <td><input name="Submit" type="submit" value="Check the Credit Card Number" onclick="Validate()" ></input></td>
  </tr>
  </table>
  </form>
  </body>
  </html>


(C) Æliens 20/2/2008

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