JAVASCRIPT - isURL BY INTERNATIONAL STANDARDS

function isIRI(url,mode){
    // CHECK URL AND MODE IS UNDEFINED WILL RETURN FALSE
    if(typeof(url)==="undefined" || typeof(mode)==="undefined"){return false;}

    // CHECK URL AND MODE IS NULL WILL RETURN FALSE
    if(url==null || mode==null){return false;}

    //TRIM URL AND MODE
    url = url.toString().replace(/^\s\s*/,'').replace(/\s\s*$/,'');
    mode = mode.toString().replace(/^\s\s*/,'').replace(/\s\s*$/,'');

    // CHECK URL AND MODE IS EMPTY WILL RETURN FALSE
    if(url=="" || mode==""){return false;}

    //  INTERNATIONAL STANDARDS FOR URL

    //  IRIS
    //  RFC 3987 : INTERNATIONALIZED RESOURCE IDENTIFIERS (IRIS)
    //  http://www.ietf.org/rfc/rfc3987

    //  RFC 2234 : AUGMENTED BNF FOR SYNTAX SPECIFICATIONS: ABNF
    //  http://www.ietf.org/rfc/rfc2234

    var ALPHA="[a-z]";
    var HEXDIG="[\\da-f]";
    var IPv6address="";

    var DIGIT="\\d";
    var genDelims="[:\\/\\?#\\[\\]@]";
    var subDelims="[!\\$&'\\(\\)\\*\\+,;=]";
    var reserved="("+genDelims+"|"+subDelims+")";
    var unreserved="("+ALPHA+"|"+DIGIT+"|-"+"|\\."+"|_"+"|~"+")";
    var pctEncoded="("+"%"+HEXDIG+"{2}"+")";
    var decOctet="("+DIGIT+"|[1-9]"+DIGIT+"|1"+DIGIT+DIGIT+"|2"+"[0-4]"+DIGIT+"|25"+"[0-5]"+")";
    var IPv4address="("+decOctet+"\\."+decOctet+"\\."+decOctet+"\\."+decOctet+")";
    var h16=HEXDIG+"{1,4}";
    var ls32="("+"("+h16+":"+h16+")"+"|"+IPv4address+")";
    var IPvFuture="("+"v"+HEXDIG+"{1,}"+"\\."+"("+unreserved+"|"+subDelims+"|:"+")+"+")";
    var IPLiteral="("+"\\["+"("+IPv6address+"|"+IPvFuture+")"+"\\]"+")";
    var port=DIGIT+"*";
    var scheme="("+ALPHA+"("+ALPHA+"|"+DIGIT+"|\\+"+"|-"+"|\\."+")*"+")";
    var iprivate="["+"\\uE000-\\uF8FF"+"]";
    var ucschar="["+"\\u00A0-\\uD7FF"+"\\uF900-\\uFDCF"+"\\uFDF0-\\uFFEF"+"]";
    var iunreserved="("+ALPHA+"|"+DIGIT+"|-"+"|\\."+"|_"+"|~"+"|"+ucschar+")";
    var ipchar="("+iunreserved+"|"+pctEncoded+"|"+subDelims+"|:"+"|@"+")";
    var ifragment="("+ipchar+"|\\/"+"|\\?"+")*";
    var iquery="("+ipchar+"|"+iprivate+"|\\/"+"|\\?"+")*";
    var isegment=ipchar+"*";
    var isegmentNz=ipchar+"+";
    var isegmentNzNc="("+iunreserved+"|"+pctEncoded+"|"+subDelims+"|@"+")+";
    var ipathAbempty="("+"\\/"+isegment+")*";
    var ipathAbsolute="("+"\\/"+"("+isegmentNz+"("+"\\/"+isegment+")*"+")?"+")";
    var ipathNoscheme="("+isegmentNzNc+"("+"\\/"+isegment+")*"+")";
    var ipathRootless="("+isegmentNz+"("+"\\/"+isegment+")*"+")";
    var ipathEmpty="("+ipchar+"){0}";
    var ipath="("+ipathAbempty+"|"+ipathAbsolute+"|"+ipathNoscheme+"|"+ipathRootless+"|"+ipathEmpty+")";
    var iregName="("+iunreserved+"|"+pctEncoded+"|"+subDelims+")*";
    var ihost="("+IPLiteral+"|"+IPv4address+"|"+iregName+")";
    var iuserinfo="("+iunreserved+"|"+pctEncoded+"|"+subDelims+"|:"+")*";
    var iauthority="("+"("+iuserinfo+"@)?"+ihost+"(:"+port+")?"+")";
    var irelativePart="("+"\\/\\/"+iauthority+ipathAbempty+"|"+ipathAbsolute+"|"+ipathNoscheme+"|"+ipathEmpty+")";
    var irelativeRef="("+irelativePart+"(\\?"+iquery+")?"+"(\\#"+ifragment+")?"+")";
    var ihierPart="("+"\\/\\/"+iauthority+ipathAbempty+"|"+ipathAbsolute+"|"+ipathRootless+"|"+ipathEmpty+")";
    var absoluteIRI="("+scheme+":"+ihierPart+"("+iquery+")?"+")";
    var IRI=scheme+":"+ihierPart+"(\\?"+iquery+")?"+"(\\#"+ifragment+")?";
    var IRIReference="("+IRI+"|"+irelativeRef+")";

    //  INTERNATIONALIZED URLS FOR THE HTTP SCHEME

    //  RFC 2616 : HYPERTEXT TRANSFER PROTOCOL -- HTTP/1.1
    //  http://www.ietf.org/rfc/rfc2616

    //  RFC 3986 : UNIFORM RESOURCE IDENTIFIER (URI): GENERIC SYNTAX
    //  http://www.ietf.org/rfc/rfc3986

    //  RFC 2396 : UNIFORM RESOURCE IDENTIFIERS (URI): GENERIC SYNTAX (OBSELETED BY RFC 3986)
    //  http://www.ietf.org/rfc/rfc2396

    var ialpha="("+ALPHA+"|"+ucschar+")";
    var ialphaNum="("+ALPHA+"|"+DIGIT+"|"+ucschar+")";
    var idomainLabel="("+ialphaNum+"|("+ialphaNum+iunreserved+"*"+ialphaNum+")"+")";

    // USES UNRESERVED CHARACTERS FROM [RFC 3987] IRI
    var itopLabel="("+ialpha+"|("+ialpha+iunreserved+"*"+ialpha+")"+")";
    var ihostName="("+idomainLabel+"\\."+")*"+itopLabel+"\\.?";

    switch(mode){
        case "IRI": break;
        case "IRI,HTTP,HTTPS":
            scheme="(https?)";
            ihost="("+IPLiteral+"|"+IPv4address+"|"+ihostName+")";  // [RFC 2396] URI GENERIC SYNTAX -> MODIFIED TO ALLOW IPLITERAL
            iauthority="("+"("+iuserinfo+"@)?"+ihost+"(:"+port+")?"+")";    // [RFC 3987] IRI
            IRI=scheme+":\\/\\/"+iauthority+ipathAbsolute+"?"+"(\\?"+iquery+")?"+"(\\#"+ifragment+")?";
            break;
        case "IRI,HTTP,HTTPS,FTP":
            // INTERNATIONALIZED URLS FOR THE HTTP(S) AND FTP SCHEMES
            scheme="(https?|ftp)";
            ihost="("+IPv4address+"|"+ihostName+")";    // [RFC 2396] URI GENERIC SYNTAX
            iauthority="("+"("+iuserinfo+"@)?"+ihost+"(:"+port+")?"+")";    // [RFC 3987] IRI
            IRI=scheme+":\\/\\/"+iauthority+ipathAbsolute+"?"+"(\\?"+iquery+")?"+"(\\#"+ifragment+")?";
            break;
    }
    return RegExp("^"+IRI+"$", "i").test(url);
}
function Checker(){
    var url = prompt("ENTER URL");
    var mode = prompt("ENTER MODE\r\n1: IRI\r\n2: IRI,HTTP,HTTPS\r\n3: IRI,HTTP,HTTPS,FTP");
    switch(mode){
        case "1": mode = "IRI"; break;
        case "2": mode = "IRI,HTTP,HTTPS"; break;
        case "3": mode = "IRI,HTTP,HTTPS,FTP"; break;
    }
    alert(isIRI(url,mode));
    Checker();
}
Checker();