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Editorial Team
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Asked: 2026-05-27T23:11:07+00:00

Why this is not point to js global scope in the code below ?

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Why this is not point to js global scope in the code below ?

<html>
<head></head>
<body>
<script type="text/javascript">

var valueHolder = {
    value: '',
    setValue: function(newValue) {
        this.value = newValue;
    },
    getValue: function() {
        return this.value;
    }
}

valueHolder.setValue("hello world");

alert(valueHolder.getValue()); // return "hello world"
alert(valueHolder.value);      // return "hello world"
alert(window.value);           // return "undefined"

</script>
</body>
</html>
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1 Answer

  1. Editorial Team

    Depends on the reference to the function (c.f. 11.2.3 of the spec):

    var valueHolder = {
    value: '',
    setValue: function(newValue) {
        this.value = newValue;
    },
    getValue: function() {
        return this.value;
    }
}

var set = valueHolder.setValue,
    get = valueHolder.getValue;

set('test');

alert(get());                  // return "test"
alert(valueHolder.value);      // return ""
alert(window.value);           // return "test"

    When referred to in context this is set to the relevant context (valueHolder in your example). In my example above, the function definitions are clearly identical, but the function references are not in the context of any object, and in that case this is set to the global context (window).

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