How to disable Drop and Drag on HTML elements

如何阻止 IE 下元素的鼠标拖拽动作

如 <a> <img> 元素

a.onmousedown = function(){
	if(event.preventDefault){
		event.preventDefault();
	}
	else{
		event.returnValue = false; 
	}
	return false;
}

but it's not working on IE. tag A and IMG

---

属性draggable=false

---

ondragstart="return false"