使弹出式窗口不可阻挡

Question

我有此代码：

<script language="JavaScript">
win2=window.open('https://www.google.com/?IDP=9698&banner_id=19845','popupad','width=300,height=300,toolbar=0,status=0,menubar=0,scrollbars=0,resizable=0,location=1')
win2.blur()
window.focus()
</script>

但是浏览器仍在阻止它。如何使此代码不受浏览器的阻止？