js에서 만든 스크롤 bar_javascript 기술의 작은 예

JS 사용자 정의 스크롤 막대를 작성했습니다. 먼저 데모를 살펴보세요(여기를 클릭하세요) 먼저

두 개의 데모가 있는데, 오른쪽의 검은색은 제가 처음에 작성한 상대적으로 피상적인 코드입니다.

코드 복사 코드는 다음과 같습니다.

var scrollself=(function(){

    var scrollblock, //滚动块
        scrollcontent,  //被滚动的内容
        scrollbar,    //滚动条
        scrollpanel,    //滚动内容的滚动区域
        cdistance,  //滚动内容要滚动的距离
        bdistance,    //滚动块要滚动的距离
        minuTop, //滚动条头尾剩下的空白
        cTop,    //滚动内容的top
        startY=0,    //滚动动作开始初鼠标的位置
        bTop=0,    //滚动动作开始初滚动块的top
        isDrag=false;  //是否拉动滚动块

    function prevent(e){

        if(e.preventDefault){
            e.preventDefault();
        }
        if(e.stopPropagation){
            e.stopPropagation();
        }
        e.cancelBubble=true;
        e.returnValue=false;
    }

    function mouseDown(event){
        isDrag=true;
        event=event||window.event;
        startY=event.clientY;
        bTop=scrollblock.offsetTop;
        cTop=scrollcontent.offsetTop;

        // prevent(event);

    }

    function mouseMove(event){
        if(isDrag){

            event=event||window.event;

            var newbTop=event.clientY-startY+bTop,
                newcTop=cTop-(event.clientY-startY)/bdistance*cdistance;

            if(newbTop newbTop=minuTop;
newcTop=0;
}else{
if(newbTop>bdistance+minuTop){
                    newcTop=-cdistance;
                    newbTop=bdistance+minuTop;
                }
            }

            scrollblock.style.top=newbTop+'px';
            scrollcontent.style.top=newcTop+'px';
        }else{
            isDrag=false;
        }

        // prevent(event);
    }

    function mouseUp(event){

        isDrag=false;

        // prevent(event);
    }

    function addHandler(){
        scrollblock.onmousedown=mouseDown;
        scrollblock.onmousemove=mouseMove;
        scrollblock.onmouseup=mouseUp;
        document.onmouseup=mouseUp;
    }

    return{
        init:function(scrollpanel_id,scrollcontent_id,scrollbar_id,scrollblock_id){
            scrollblock=document.getElementById(scrollblock_id);
            scrollcontent=document .getElementById(scrollcontent_id);
> stance=scrollcontent.offsetHeight-scrollpanel.offsetHeight;
            bdistance=scrollbar .offsetHeight-minuTop*2-scrollblock.offsetHeight;

            enclose(scrollpanel,scrollcontent,scrollbar,scrollblock,bdistance,cdistance,minuTop);
           addHandler();
        }
    }


}());

scrollself.init('scrollpanel2','scrollcontent2','scrollbar2','scrollblock2');

因为很卡，저희는 就又上网看了一下别人的代码，然后把根据别人的思路把代码改了一下，很明显，效果好了很多，代码：

复主代码

代码如下:

var scroll=(function(){

    var scrollblock, //滚动块
        scrollcontent,  //被滚动的内容
        scrollbar,    //滚动条
        scrollpanel,    //滚动内容的滚动区域
        cdistance,  //滚动内容要滚动的距离
        bdistance,    //滚动块要滚动的距离
        minuTop, //滚动条头尾剩下的空白
        cTop,    //滚动内容的top
        startY=0,    //滚动动作开始初鼠标的位置
        bTop=0;    //滚动动作开始初滚动块的top

    function mouseDown(event){
        event=event||window.event;
        startY=event.clientY;
        bTop=scrollblock.offsetTop;
        cTop=scrollcontent.offsetTop;
        if(scrollblock.setCapture){

            scrollblock.onmousemove=doDrag;
            scrollblock.onmouseup=stopDrag;
            scrollblock.setCapture();
        }else{
            document.addEventListener("mousemove",doDrag,true);
            document.addEventListener("mouseup",stopDrag,true);
        }

    }

    function doDrag(event){
        event=event||window.event;

        var newbTop=event.clientY-startY+bTop,
            newcTop=cTop-(event.clientY-startY)/bdistance*cdistance;

        if(newbTop newbTop=minuTop;
newcTop=0;
}else if(newbTop>bdistance+minuTop){
            newcTop=-cdistance;
            newbTop=bdistance+minuTop;
        }
        scrollblock.style.top=newbTop+'px';
        scrollcontent.style.top=newcTop+'px';

    }

    function stopDrag(event){
        if(scrollblock.releaseCapture){

            scrollblock.onmousemove=doDrag;
            scrollblock.onmouseup=stopDrag;
            scrollblock.releaseCapture();
       }else{
            document.re moveEventListener("mousemove",doDrag,true);
           document.removeEventListener("mouseup",stopDrag,true);
        }
        scrollblock.onmousemove=null;
        scrollblock.onmouseup=null;
    }
    반환{
        초기화 :function(scrollpanel_id,scrollcontent_id,scrollbar_id,scrollblock_id){
            scrollblock=document.getElementById(scrollblock_id);
            scrollcontent=document.getElementById(scrollcontent_id);
            스크롤바=document.getElementById(scrollbar_id);
> 거리=scrollbar.offsetHeight-minuTop*2-scrollblock.offsetHeight;
            scrollblock.onmousedown=mouseDown;
            enclose(scrollpanel,scrollcontent,scrollbar,scrollblock,bdistance,cdistance,minuTop);
        }
    }

}());

scroll.init('scrollpanel','scrollcontent','scrollbar','scrollblock');

比较了一下两个的代码,其实修改的不多，就有一点很大不同，流畅的那一个（左边绿color那一个）多了这个东西——setCapture、releaseCapture。

具体是怎样的，再研究一下先。