Opfat String som objekt!?

Lidt kode:

<html>
<head>
    <title>Untitled</title>
</head>

<body>

<script language=\"JavaScript\">

function validate(formfields)
{
alert(\"valider \" +formfields);
splitname = formfields.split(\",\");
var docfirst = \"document.form.\"
var container = \"\";
var i;

    for(i = 0; i < splitname.length; i++)
    {
        container = docfirst+splitname[i];
        alert(container);
    }

    for(i = 0; i < splitname.length; i++)
    {
        if(eval(splitname[i].value == \"\"))
        { 
            alert(\"Feltet skal være udfyldt\");
            splitname[i].value = \"Tis\";
            return false;
        }
    }
}
</script>

<form name = \"form\">
<input type = \"text\" name = \"f1\" val = \"comment\" size = \"9\"><br>
<input type = \"text\" name = \"f2\" val = \"comment\" size = \"9\"><br>
<input type = \"text\" name = \"f3\" val = \"comment\" size = \"9\"><br>
<input type = \"text\" name = \"f4\" val = \"comment\" size = \"9\"><br>
<input type = \"text\" name = \"f5\" val = \"comment\" size = \"9\"><br>
<input type = \"text\" name = \"f6\" val = \"comment\" size = \"9\"><br>
<input type = \"button\" value = \"Validate\" onClick = java script:validate(\"f1,f2,f3\");>
</form>

</body>
</html>

Hvordan får jeg lavet strengene om til objekter så den sidste forløkke opfatter arrayelementerne som objekter af document.x.x.x??