关闭当前页面

function closewin(){  
    if (navigator.userAgent.indexOf("Firefox") != -1 || navigator.userAgent.indexOf("Chrome") !=-1) {  
        window.location.href="about:blank";  
        window.close();  
    } else {  
        window.opener = null;  
        window.open("", "_self");  
        window.close();  
    }  
}