Web button to act as a push button and not as a switch (not latching)

Hi guys,
I am using a sketch that it works fine for a web server and i can switch on and off all my relays for my project with the if command
if (readString.indexOf("?button4on") >0){
digitalWrite(led3, LOW);
}
if (readString.indexOf("?button4off") >0){
digitalWrite(led3, HIGH);
}
Everything was going good until now.
Now i need to operate a impulse relay and i don't know which code to use so i will make my "web button" to act like a simple button and not like a switch as i had it.
Thank u in advance for ur time.

It sounds like you need something like

if (readString.indexOf("?button4on") >0)
  {
     digitalWrite(led3, LOW);
     delay(aWhile);
     digitalWrite(led3, HIGH);
  }

How long you delay() is up to you and how long the impulse needs to be. Note that if the code is to remain responsive then you will need to keep the delay() very short or, better, use millis() for timing to avoid blocking code execution.

If you use the timed method, readString would need to be cleared somewhere (possibly like below) before the test loop is run again.

if (readString.indexOf("?button4on") >0)
  {
     digitalWrite(led3, LOW);
     delay(aWhile);
     digitalWrite(led3, HIGH);
     readString="";
  }

Thank you very much both.
I ll try it tonight. i am sure that it will work