Why .includes on string doesn’t detect lower case letters?

I wrote this to detect if the url contain this particular keyword i.e. recordId but if url contains it in lower i.e. recordid then it doesn’t detect.

How do I make them detect both because data can have both recordid or recordId.

if(url && url.includes("recordId") && url.includes("rt")){
      this._geRecordId(url);
    } 

 private async geRecordId(url){
    const linkedId = this._getURLValue('recordId' , url);
    if(!linkedId){
      return;
    }

private _getURLValue( name, url ) {
    if (!url) url = location.href;
    name = name.replace(/[[]/,"\[").replace(/[]]/,"\]");
    var regexS = "[\;]"+name+"=([^;]*)";
    var regex = new RegExp( regexS );
    var results = regex.exec( url );
    return results == null ? null : results[1];
 }

I tried changing regex