JavaScript question

Is it possible to program a code that allows a attack button to automatically do hp like these examples 

Code:



[code]

 document.getElementById("attack").click(); = dragon.hp = dragon.hp - 10;

[size=13][code]document.getElementById("attack").onclick = function(){
    dragon.hp -[/code][/size]
[size=13][code]document.getElementById("attack").addEventListener('click', function(){
    dragon.hp -= 10;
});[/code]
[code]dragon.hp -= 10;[/code]

[code]dragon.hp = dragon.hp - 10;[/code][
   <a ..... onClick="deductHpPoints()">...</a>[/code][code]            Function deductHpPoints()
            {
              //deduct logic
             }[/code]
[color=#000000]

Like this code shown to work with a rpg character sheet