Regex should allow only http(s) Protocol

function onChange(control, oldValue, newValue, isLoading) {
    if (isLoading || newValue == '') {
          return;
    }
  g_form.hideErrorBox('url');
       var pattern =/https?:\/\/(www\.)?[-a-zA-Z0-9@:%._\+~#=]{2,256}\.[a-z]{2,6}\b([-a-zA-Z0-9@:%_\+.~#()?&//=]*)/    // regex pattern
   if(!pattern.test(newValue)){
     g_form.showErrorBox('url', getMessage('Please provide Valid URL'));//show error messege
           g_form.setValue('url', '');
   }
}

Example:

https://www.workingcode.in/question/regex-validation-only-alphanumeric-with-space-allowed-servicenow/
 http://www.workingcode.in/
 http://11.21.123.12