让起点的文章可复制粘贴的代码

document.onselectstart = null;
var cons = document.querySelectorAll('*'); 
for(var i=0; i < cons.length; i++) {
    cons[i].onmousedown = null; 
    cons[i].onmouseup = null;
    cons[i].onclick = null;
    cons[i].onselectstart = null
}