Numeric Check with some Regular Expression magic

<script language="javascript" runat="server">
    // Checks that the string supplied can be expressed as a number (float)
    function isNumeric(strNumber) {
        return (strNumber.search(/^(-|\+)?\d+(\.\d+)?$/) != -1);
    }

    // Checks that the string supplied can be expressed as an unsigned number (float)
    function isUnsignedNumeric(strNumber) {
        return (strNumber.search(/^\d+(\.\d+)?$/) != -1);
    }

    // Checks that the string supplied can be expressed as an integer
    function isInteger(strInteger) {
        return (strInteger.search(/^(-|\+)?\d+$/) != -1);
    }

    // Checks that the string supplied can be expressed as an unsigned integer
    function isUnsignedInteger(strInteger) {
        return (strInteger.search(/^\d+$/) != -1);
    }
</script>