Why do I need to add index 1 to my childNodes array, when I want to get the first child?
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I have a function in javascript which should output a text entered into an input field.
My code:

    <head>
        <script type="text/javascript">
        function calculate()
        {
	        var input = document.body.childNodes[1];
	        document.write(input.value);
        }
        </script>
    </head>

    <body>
        <input type="text"/>
        <input type="button" onclick="calculate()"/>
    </body>

Now what I don´t understand is why do I have to put the index "1" into my childNodes array? Logically it should be "0" since `<input type="text"/>` is the first child of body.