How to insert the PHP file demonstration of starting SMS sending into the countdown sending button code below. Ask the great god to help write it.

& lthtml & gt

& lthead & gt

& lt script? type =“text/JavaScript“& gt； ?

var？ Countdown =180; ?

Function? settime（obj）？ {?

What if? (countdown? ==? 0)? {?

obj . remove attribute（“disabled“）； ?

Obj.value= "Get the verification code for free"; ?

Countdown? =? 180; ?

Return;

}? Or what? If (countdown? ==? 180){?

//ajax code to start SMS sending is written here. You didn't provide specific information, so you must write it yourself.

}

obj . set attribute（“disabled“，？ True); ?

Obj.value= "resend (? +? Countdown? +? ")"; ?

Countdown-; ?

setTimeout（function（）？ {?

settime（obj）；

}, 1000);

}

& lt/script & gt；

& ltbody & gt？

& lt input? type =“button“？ id =“BTN“？ Value= "Get verification code for free"? onclick =“settime（this）“？ /& gt； ?

& lt/body & gt；

& lt/html & gt；