用JavaScript实现上下文字滚动特效

　文字左右滚动的走马灯效果是一种非常容易实现的特效，同样的，文字上下滚动循环显示也是一种非常常见而且非常容易实现的文字特效。

　具体实现方法如下：

<script language=JavaScript>
var messages=new Array()
messages[0]="<font color=#8000FF>欢迎光临Looky's Blog!</font></a>"
messages[1]="<font color=#FB2500>这是一个用JavaScript实现上下文字滚动特效的例子</font></a>"
messages[2]="<font color=#FF0066F>希望这个例子能帮助到你</font></a>"
messages[3]="<font color=#FF9900>这里的代码你可以随便转载</font></a>"
messages[4]="<font color=#00CC33>这里的所有一切都是免费的</font></a>"
messages[5]="<font color=#000000>这里有…………有精彩的内容等着你</font></a>"

var scrollerwidth=320
var scrollerheight=100
var scrollerbgcolor='#FFFFFF'
//下面的代码不要改动
if (messages.length>1)
i=2
else
i=0
function move1(whichlayer){
tlayer=eval(whichlayer)
if (tlayer.top>0&&tlayer.top<=5){
tlayer.top=0
setTimeout("move1(tlayer)",3000)
setTimeout("move2(document.main.document.second)",3000)
return}
if (tlayer.top>=tlayer.document.height*-1){
tlayer.top-=5
setTimeout("move1(tlayer)",100)}
else{
tlayer.top=scrollerheight
tlayer.document.write(messages[i])
tlayer.document.close()
if (i==messages.length-1)
i=0
else
i++}}
function move2(whichlayer){
tlayer2=eval(whichlayer)
if (tlayer2.top>0&&tlayer2.top<=5){
tlayer2.top=0
setTimeout("move2(tlayer2)",3000)
setTimeout("move1(document.main.document.first)",3000)
return}
if (tlayer2.top>=tlayer2.document.height*-1){
tlayer2.top-=5
setTimeout("move2(tlayer2)",100)}
else{
tlayer2.top=scrollerheight
tlayer2.document.write(messages[i])
tlayer2.document.close()
if (i==messages.length-1)
i=0
else
i++}}
function move3(whichdiv){
tdiv=eval(whichdiv)
if (tdiv.style.pixelTop>0&&tdiv.style.pixelTop<=5){
tdiv.style.pixelTop=0
setTimeout("move3(tdiv)",3000)
setTimeout("move4(second2)",3000)
return}
if (tdiv.style.pixelTop>=tdiv.offsetHeight*-1){
tdiv.style.pixelTop-=5
setTimeout("move3(tdiv)",100)}
else{
tdiv.style.pixelTop=scrollerheight
tdiv.innerHTML=messages[i]
if (i==messages.length-1)
i=0
else
i++}}
function move4(whichdiv){
tdiv2=eval(whichdiv)
if (tdiv2.style.pixelTop>0&&tdiv2.style.pixelTop<=5){
tdiv2.style.pixelTop=0
setTimeout("move4(tdiv2)",3000)
setTimeout("move3(first2)",3000)
return}
if (tdiv2.style.pixelTop>=tdiv2.offsetHeight*-1){
tdiv2.style.pixelTop-=5
setTimeout("move4(second2)",100)}
else{
tdiv2.style.pixelTop=scrollerheight
tdiv2.innerHTML=messages[i]
if (i==messages.length-1)
i=0
else
i++}}
function startscroll(){
if (document.all){
move3(first2)
second2.style.top=scrollerheight}
else if (document.layers){
move1(document.main.document.first)
document.main.document.second.top=scrollerheight+5
document.main.document.second.visibility='show'}}
window.onload=startscroll
</script>
<ilayer id="main" width=&{scrollerwidth}; height=&{scrollerheight};
bgcolor=&{scrollerbgcolor};>
<layer id="first" left=0 top=1 width=&{scrollerwidth};>
<script language="JavaScript1.2">
if (document.layers)
document.write(messages[0])
</script>
</layer>
<layer id="second" left=0 top=0 width=&{scrollerwidth}; visibility=hide>
<script language="JavaScript1.2">
if (document.layers)
document.write(messages[1])
</script>
</layer>
</ilayer>
<script language="JavaScript1.2">
if (document.all){
document.writeln('<span id="main2" style="position:relative;width:'+scrollerwidth+';height:'
+scrollerheight+';overflow:hiden;background-color:'+scrollerbgcolor+'">')
document.writeln('<div style="position:absolute;width:'+scrollerwidth+';height:'
+scrollerheight+';clip:rect(0 '+scrollerwidth+' '
+scrollerheight+' 0);left:0;top:0">')
document.writeln('<div id="first2" style="position:absolute;width:'+scrollerwidth+';left:0;top:1;">')
document.write(messages[0])
document.writeln('</div>')
document.writeln('<div id="second2" style="position:absolute;width:'+scrollerwidth+';left:0;top:0">')
document.write(messages[1])
document.writeln('</div>')
document.writeln('</div>')
document.writeln('</span>')
}
</script>

(在需要添加该特效的网页具体位置中粘贴如下代码即可)

　　注意：代码中的“var scrollerwidth=320”表示循环框宽度，"var scrollerheigh=100"表示循环框高度，"font color=# "代表文字颜色，可以根据需要进行修改。