chapter: Regular Expressions
==================
var parse_url = /^(?:([A-Za-z]+):)?(\/{0,3})([0-9.\-A-Za-z]+)
(?::(\d+))?(?:\/([^?#]*))?(?:\?([^#]*))?(?:#(.*))?$/;

var url = "http://www.ora.com:80/goodparts?q#fragment";
    
    
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var url = "http://www.ora.com:80/goodparts?q#fragment";

var result = parse_url.exec(url);

var names = ['url', 'scheme', 'slash', 'host', 'port',
    'path', 'query', 'hash'];

var blanks = '       ';
var i;

for (i = 0; i < names.length; i += 1) {
    document.writeln(names[i] + ':' +
        blanks.substring(names[i].length), result[i]);
}
    
    
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url:    http://www.ora.com:80/goodparts?q#fragment
scheme: http
slash:  //
host:   www.ora.com
port:   80
path:   goodparts
query:  q
hash:   fragment
    
    
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^
    
    
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(?:([A-Za-z]+):)?
    
    
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(\/{0,3})
    
    
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([0-9.\-A-Za-z]+)
    
    
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(?::(\d+))?
    
    
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(?:\/([^?#]*))?
    
    
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(?:\?([^#]*))?
    
    
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(?:#(.*))?
    
    
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$
    
    
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var parse_number = /^-?\d+(?:\.\d*)?(?:e[+\-]?\d+)?$/i;

var test = function (num) {
    document.writeln(parse_number.test(num));
};

test('1');                // true
test('number');           // false
test('98.6');             // true
test('132.21.86.100');    // false
test('123.45E-67');       // true
test('123.45D-67');       // false
    
    
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/^   $/i
    
    
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-?
    
    
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\d+
    
    
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(?:\.\d*)?
    
    
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(?:e[+\-]?\d+)?
    
    
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// Make a regular expression object that matches
// a JavaScript string.

var my_regexp = /"(?:\\.|[^\\\"])*"/g;
    
    
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// Make a regular expression object that matches
// a JavaScript string.

var my_regexp = new RegExp("\"(?:\\\\.|[^\\\\\\\"])*\"", 'g');
    
    
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function make_a_matcher(  ) {
    return /a/gi;
}

var x = make_a_matcher(  );
var y = make_a_matcher(  );

// Beware: x and y are the same object!

x.lastIndex = 10;

document.writeln(y.lastIndex);    // 10
    
    
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"into".match(/in|int/)
    
    
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\ / [ ] ( ) { } ? + * | . ^ $
    
    
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var doubled_words = /([A-Za-z\u00C0-\u1FFF\u2800-\uFFFD]+)\s+\1/gi;
    
    
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! " # $ % & ' ( ) * +, - . / :
; < = > ? @ [ \ ] ^ _ ` { | } ˜
    
    
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(?:!|"|#|\$|%|&|'|\(|\)|\*|\+|,|-|\.|\/|:|;|<|=|>|@|\[|\\|]|\^|_|` |\{|\||\}|˜)
    
    
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[!-\/:-@\[-`{-˜]
    
    
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- / [ \ ] ^
    
    
==================