层跟随页面上下滚动的问题，急！！

判断一下滚动前的document.body.scrollTop和滚动后的document.body.scrollTop是否相等/

解决方案 »

  1.   

    <HTML>
    <HEAD>
    <TITLE>随滚动条移动的层</TITLE>
    <META HTTP-EQUIV="Content-Type" CONTENT="text/html" charset="gb2312">
    </HEAD>
    <style>
    <!--
    .div{
     position: absolute;
     border: 2px solid red;
     background-color: #EFEFEF;
     line-height:90px;
     font-size:12px;
     z-index:1000;
    }
    -->
    </style>
    <BODY>
    <div id="Javascript.Div1" class="div" style="width: 240; height:90" align="center">正中...</div>
    <SCRIPT LANGUAGE="JavaScript">
    function sc1(){
     document.getElementById("Javascript.Div1").style.top=document.body.scrollTop+(document.body.clientHeight-document.getElementById("Javascript.Div1").offsetHeight)/2
     document.getElementById("Javascript.Div1").style.left=document.body.scrollLeft+(document.body.clientWidth-document.getElementById("Javascript.Div1").offsetWidth)/2;
    }
    </SCRIPT>
    <div id="Javascript.Div2" class="div" style="width: 240; height:90;" align="center">左上...</div>
    <SCRIPT LANGUAGE="JavaScript">
    function sc2(){
     document.getElementById("Javascript.Div2").style.top=document.body.scrollTop
     document.getElementById("Javascript.Div2").style.left=document.body.scrollLeft;
    }
    </SCRIPT><div id="Javascript.Div3" class="div" style="width: 240; height:90;" align="center">左下...</div>
    <SCRIPT LANGUAGE="JavaScript">
    function sc3(){
     document.getElementById("Javascript.Div3").style.top=document.body.scrollTop+document.body.clientHeight-document.getElementById("Javascript.Div3").offsetHeight;
     document.getElementById("Javascript.Div3").style.left=document.body.scrollLeft;
    }
    </SCRIPT><div id="Javascript.Div4" class="div" style="width: 240; height:90;" align="center">右上...</div>
    <SCRIPT LANGUAGE="JavaScript">
    function sc4(){
     document.getElementById("Javascript.Div4").style.top=document.body.scrollTop;
     document.getElementById("Javascript.Div4").style.left=document.body.scrollLeft+document.body.clientWidth-document.getElementById("Javascript.Div4").offsetWidth;
    }
    </SCRIPT><div id="Javascript.Div5" class="div" style="width: 240; height:90;" align="center">右下...</div>
    <SCRIPT LANGUAGE="JavaScript">
    function sc5(){
     document.getElementById("Javascript.Div5").style.top=document.body.scrollTop+document.body.clientHeight-document.getElementById("Javascript.Div5").offsetHeight;
     document.getElementById("Javascript.Div5").style.left=document.body.scrollLeft+document.body.clientWidth-document.getElementById("Javascript.Div5").offsetWidth;;
    }
    </SCRIPT>
    <SCRIPT LANGUAGE="JavaScript">
    <!--
    function scall(){
     sc1();sc2();sc3();sc4();sc5();
    }
    window.onscroll=scall;
    window.onresize=scall;
    window.onload=scall;
    //-->
    </SCRIPT>
    <div style="position: absolute; top: 0; left: 0; width: 10000; height: 4000;"></div>
    </BODY>
    </HTML>