本文实例讲述了JS模拟简易滚动条效果的方法。分享给大家供大家参考，具体如下：

使用Js模拟滚动条。简易模式，类似手机上常见的滚动条。

效果如下：

Js代码如下：

var scrollMoveObj = null, scrollPageY = 0, scrollY = 0; var scrollDivList = new Array(); // obj需要添加滚动条的对象 w滚动条宽度 className滚动条样式名称 // obj元素 必须指定高度，并设置overflow:hidden; // 如要兼容IE6 必须给obj元素 指定 overflow:hidden; function jsScroll(obj, w, className) { if(typeof(obj) == 'string') { obj = document.getElementById(obj); } //当内容未超出现在高度时，不添加滚动条 if(!obj || obj.scrollHeight <= obj.clientHeight || obj.clientHeight == 0) { return; } obj.scrollBarWidth = w||6; obj.style.overflow = 'hidden'; obj.scrollBar = document.createElement('div'); document.body.appendChild(obj.scrollBar); obj.scrollBarIndex = document.createElement('div'); obj.scrollBar.appendChild(obj.scrollBarIndex); obj.scrollBar.style.position = 'absolute'; obj.scrollBarIndex.style.position = 'absolute'; obj.scrollBar.className = className || ''; if(!className) { obj.scrollBar.style.backgroundColor = '#ddd'; obj.scrollBarIndex.style.backgroundColor = '#aaa'; } scrollDivList.push(obj); scrollResetSize(obj); //使用鼠标滚轮滚动 obj.scrollBar.scrollDiv = obj; obj.scrollBarIndex.scrollDiv = obj; obj.onmousewheel = scrollMove; obj.scrollBar.onmousewheel = scrollMove; obj.scrollBarIndex.onmousewheel = scrollMove; //拖动滚动条滚动 obj.scrollBarIndex.onmousedown = function(evt){ evt = evt || event; scrollPageY = evt.clientY; scrollY = this.scrollDiv.scrollTop; isScrollMove = true; document.body.onselectstart = function(){return false}; scrollMoveObj = this.scrollDiv; if(this.scrollDiv.scrollBar.className == '') { this.scrollDiv.scrollBarIndex.style.backgroundColor = '#888'; } return false; } } //当页面大小发生变化时，重新计算滚动条位置 window.onresize = function(){ for(var i=0; i<scrollDivList.length; i++) { scrollResetSize(scrollDivList[i]); } } //计算滚动条位置 function scrollResetSize(o) { if(o.scrollHeight <= o.clientHeight) { o.scrollTop = 0; o.scrollBar.style.display = 'none'; } else { o.scrollBar.style.display = 'block'; } var x=0, y=0; var p = o; while(p) { x += p.offsetLeft; y += p.offsetTop; p = p.offsetParent; } var borderTop = parseInt(o.style.borderTopWidth||0); var borderBottom = parseInt(o.style.borderBottomWidth||0); o.scrollBar.style.width = o.scrollBarWidth + 'px'; o.scrollBar.style.height = o.clientHeight + 'px'; o.scrollBar.style.top = y + borderTop + 'px'; o.scrollBar.style.left = x + o.offsetWidth - o.scrollBarWidth + 'px'; o.scrollBarIndex.style.width = o.scrollBarWidth + 'px'; var h = o.clientHeight - (o.scrollHeight - o.clientHeight); //当滚动条滑块最小20个像素 if(h < 20) { h = 20; } o.scrollBarHeight = h; o.scrollBarIndex.style.height = h + 'px'; o.scrollBarIndex.style.left = '0px'; setScrollPosition(o); } function setScrollPosition(o) { o.scrollBarIndex.style.top = (o.clientHeight - o.scrollBarHeight) * o.scrollTop / (o.scrollHeight - o.clientHeight) + 'px'; } document.documentElement.onmousemove = function(evt){ if(!scrollMoveObj)return; evt = evt || event; var per = (scrollMoveObj.scrollHeight - scrollMoveObj.clientHeight) / (scrollMoveObj.clientHeight - scrollMoveObj.scrollBarHeight) scrollMoveObj.scrollTop = scrollY - (scrollPageY - evt.clientY) * per; setScrollPosition(scrollMoveObj); } document.documentElement.onmouseup = function(evt){ if(!scrollMoveObj)return; if(scrollMoveObj.scrollBar.className == '') { scrollMoveObj.scrollBarIndex.style.backgroundColor = '#aaa'; } scrollMoveObj = null; document.body.onselectstart = function(){return true}; } // 鼠标滚轮滚动 function scrollMove(evt){ var div = this.scrollDiv || this; if(div.scrollHeight <= div.clientHeight) return true; evt = evt || event; var step = 20; if(evt.wheelDelta < 0) { if(div.scrollTop >= (div.scrollHeight - div.clientHeight)) return true; div.scrollTop += step; } else { if(div.scrollTop == 0) return true; div.scrollTop -= step; } setScrollPosition(div); return false; }

完整实例代码点击此处本站下载。

希望本文所述对大家JavaScript程序设计有所帮助。