[JS] Expand Abbreviated IPv6 Addresses (with support for embedded IPv4 Address)

ipv6.js

// [JS] Expand Abbreviated IPv6 Addresses
// by Christopher Miller
// http://forrst.com/posts/JS_Expand_Abbreviated_IPv6_Addresses-1OR
// Modified to work with embedded IPv4 addresses
function expandIPv6Address(address)
{
    var fullAddress = "";
    var expandedAddress = "";
    var validGroupCount = 8;
    var validGroupSize = 4;

    var ipv4 = "";
    var extractIpv4 = /([0-9]{1,3})\.([0-9]{1,3})\.([0-9]{1,3})\.([0-9]{1,3})/;
    var validateIpv4 = /((25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)(\.(25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)){3})/;

    // look for embedded ipv4
    if(validateIpv4.test(address))
    {
        groups = address.match(extractIpv4);
        for(var i=1; i<groups.length; i++)
        {
            ipv4 += ("00" + (parseInt(groups[i], 10).toString(16)) ).slice(-2) + ( i==2 ? ":" : "" );
        }
        address = address.replace(extractIpv4, ipv4);
    }

    if(address.indexOf("::") == -1) // All eight groups are present.
        fullAddress = address;
    else // Consecutive groups of zeroes have been collapsed with "::".
    {
        var sides = address.split("::");
        var groupsPresent = 0;
        for(var i=0; i<sides.length; i++)
        {
            groupsPresent += sides[i].split(":").length;
        }
        fullAddress += sides[0] + ":";
        for(var i=0; i<validGroupCount-groupsPresent; i++)
        {
            fullAddress += "0000:";
        }
        fullAddress += sides[1];
    }
    var groups = fullAddress.split(":");
    for(var i=0; i<validGroupCount; i++)
    {
        while(groups[i].length < validGroupSize)
        {
            groups[i] = "0" + groups[i];
        }
        expandedAddress += (i!=validGroupCount-1) ? groups[i] + ":" : groups[i];
    }
    return expandedAddress;
}