Prototype - Enumerable detect() Method

This method finds the first element for which the iterator returns true. This method is aliased as find() method.

Syntax

Iterator.detect([context]);

Return Value

Returns first element for which the iterator returns true otherwise undefined.

Example

<html>
   <head>
      <title>Prototype examples</title>
      <script type = "text/javascript" src = "/javascript/prototype.js"></script>
      
      <script>
         function isPrime(n) {
            if (2 > n) return false;
            if (0 == n % 2) return (2 == n);
            for (var index = 3; n / index > index; index += 2)
            if (0 == n % index) return false;
            return true;
         } // isPrime
         function showResult() {
            alert($R(10,15).detect(isPrime) );
         }
      </script>
   </head>

   <body>
      <p>Click the button to see the result.</p>
      <br />
      <br />
      <input type = "button" value = "Result" onclick = "showResult();"/>
   </body>
</html>

Output

prototype_enumerating.htm