Обработка button

window.onload = init; 
 
function init(){ 
	var button = document.getElementById("addButton"); 
	button.onclick = handleButtonClick(); 
} 
 
function handleButtonClick(){ 
	var textInput = document.getElementById("dogName"); 
	var dogName = textInput.value; 
	var textInput = document.getElementById("dogBreed"); 
	var dogBreed = textInput.value; 
	var textInput = document.getElementById("dogWeight"); 
	var dogWeight = textInput.value; 
	var dog1 = new Dog(dogName, dogBreed, dogWeight); 
	dog1.bark(); 
} 
 
function Dog(name, breed, weight){ 
	this.name = name; 
	this.breed = breed; 
	this.weight = weight; 
	this.bark = function(){ 
		if (this.weight > 25){ 
			alert(this.name + ": Вуф!!!"); 
		} else { 
			alert(this.name + ": Тяв!"); 
		} 
	}; 
}

<form> 
  <input type="text" id="dogName" size="40" placeholder="Кличка собаки"><br> 
  <input type="text" id="dogBreed" size="40" placeholder="Порода собаки"><br> 
  <input type="text" id="dogWeight" size="40" placeholder="Вес собаки"><br> 
  <input type="button" id="addButton" value="Голос!"> 
</form>