javascript中隐藏显示的样式表属性

//使用display的样式属性 隐藏 显示
//隐藏后不占据文档流位置
function showAddForm(){
	
	var attr = document.getElementById("addForm");
	if(attr.style.display == "none"){
		attr.style.display = "block";
	}else{
		attr.style.display = "none";
	}
}
//使用visibility的样式属性 隐藏 显示
//隐藏后占据文档流位置
function showVisibility(){
	var attr = document.getElementById("addForm");
	if(attr.style.visibility == "hidden"){
		attr.style.visibility = "visible";
	}else{
		attr.style.visibility = "hidden";
	}
}