let txt = "4br4k 4d4br4";
let num = txt.replace(/\D/g, "");
console.log(num);
/ Get number of string
                  Created 
                    Fri, 29 May 2020 15:39:18 +0000 
                  
                
              let txt = "4br4k 4d4br4";
let num = txt.replace(/\D/g, "");
console.log(num);