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>