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# Prototype sub() Method

This method returns a string with the first count occurrences of pattern replaced by either a regular string, the returned value of a function or a Template string. pattern can be a string or a regular expression.

## Syntax:

    string.sub(pattern, replacement[, count = 1]);

## Return Value:

- Returns a string.

## Example:

    <html>
    <head>
    <title>Prototype examples</title>
    <script type="text/javascript"
       src="/javascript/prototype.js">
    </script>
    <script>

    function showResult(){
      var fruits = 'apple pear orange';

      alert("fruits.sub(' ', ', '):"+  fruits.sub(' ', ', '));
      alert("fruits.sub(' ', ', ', 1): " +  fruits.sub(' ', ', ', 1));
      alert("fruits.sub(' ', ', ', 2): " +  fruits.sub(' ', ', ', 2));

      var str = fruits.sub(/\w+/,
          function(match){ return match[0].capitalize() + ','}, 2);
      alert(str);

    }

    </script>
    </head>

    <body>

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

    </body>
    </html>

To understand it in better way you can Try it yourself.

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