javascript检测相关

function validB(){ 
    var u_agent = navigator.userAgent; 
    var B_name="不是想用的主流浏览器!"; 
    if(u_agent.indexOf("Firefox")>-1){ 
        B_name="Firefox"; 
    }else if(u_agent.indexOf("Chrome")>-1){ 
        B_name="Chrome"; 
    }else if(u_agent.indexOf("MSIE")>-1&&u_agent.indexOf("Trident")>-1){ 
        B_name="IE(8-10)";  
    }
        document.write("浏览器:"+B_name+"<br>");
        document.write("u_agent:"+u_agent+"<br>"); 
  }

<script type="text/javascript">
    document.write( "屏幕宽度："+screen.width+"px<br/>");
    document.write( "屏幕高度："+screen.height+"px<br/>");       
</script>

<script type="text/javascript">
    document.write("可用宽度："+screen.availWidth+"px<br/>");
    document.write("可用高度："+screen.availHeight+"px<br/>" );     
</script>