<script type="text/javascript">
<!--
    var w = 123
    alert(w)
    function fun(){
    alert(w)
        w++
    alert(w)
    }
    fun()


    // 123 123 124
//-->
</script>

<script type="text/javascript">
<!--
    var w = 123
    alert(w)
    function fun(){
        var w =12
    alert(w)
        w++
    alert(w)
    }
    fun()


    // 123 12 13
//-->
</script>