Get or Set image URL and remove onclick method of HTML image in ASP.Net

Hello

How to get and set image url and remove onclick method of html image control in Code behind c#

--Design View

<img  id='07'  alt='Unbooked' onclick="seat('07')" src='images/chair/G_chair.png' style='cursor:pointer;'/>

--code behind want

07.src="";

remove onclick="seat('07')";