how can i make single choice checkbox?

Question

i want to select only one in between these 3 options where i was wrong please show me with ex. this is my code.

HTML-----

 <label for="gender1">Male</label>
 <input type="checkbox" id="gender1" onclick="select(this.id)" name="gender" value="male">
 <label for="gender2">Female</label>
 <input type="checkbox" id="gender2" onclick="select(this.id)" name="gender" value="female">
 <label for="gender3">None</label>
 <input type="checkbox" id="gender3" onclick="select(this.id)" name="gender" value="none">

Javascript-----

function select(id){
   for(var i=1;i<=3;i++){
      document.getElementById("gender" +i).checked=false;
   }
   document.getElementById(id).checked=true;
}