newbie: Array.prototype.inArray

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#51427

From: jivanmukta
Date: Wed, 25 Jun 2014 14:20

33 lines
1848 bytes

Uczę się języka JavaScript:

<html>
<head>
<title>Test</title>
</head>
<body>
<script type="text/javascript">
Array.prototype.inArray = function(needle) {
	for (var i = 0, len = this.length; i < len; i++) {
		if (this[i] == needle) {
			return true;
		}
	}
	return false;
}
var a = [1, 2, 3];
document.write(a.inArray(2) ? '1' : '0');
</script>
</body>

To działa. Ale nie rozumiem właściwie dlaczego nie mogę dodać metody inArray do Array bezpośrednio. Przecież Array to obiekt.

Array.inArray = function(needle) {
	for (var i = 0, len = this.length; i < len; i++) {
		if (this[i] == needle) {
			return true;
		}
	}
	return false;
}

Mam problem z rozumieniem prototypów,

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Subject: newbie: Array.prototype.inArray
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