function InStr(String1, String2)
{
    var a = 0;

    if (String1 == null || String2 == null)
        return (false);

    String1 = String1.toLowerCase();
    String2 = String2.toLowerCase();

    a = String1.indexOf(String2);
    if (a == -1)
        return 0;
    else
        return a + 1;
}

function Mid(String, Start, Length)
{
    if (String == null)
        return (false);

    if (Start > String.length)
        return '';

    if (Length == null || Length.length == 0)
        return (false);

    return String.substr((Start - 1), Length);
}

function Len(string)
{
    if (string == null)
        return (false);

    return String(string).length;
}


function cerca_tra_tag(stringa, tag1, tag2)
{
	tag_start = InStr(stringa,tag1) + Len(tag1)
	tag_finish = InStr(stringa,tag2)
	tag_len = tag_finish - tag_start
	risulato_cerca_tra_tag = Mid(stringa, tag_start, tag_len)
}