2012-10-21 来源:网络
【实例名称】
《黑客帝国》中的字符下落效果
【实例描述】
所有看过电影《黑客帝国》的人可能都对一个场非常熟悉,那就是一连串的0、l编码。本例学习如何制作那种字符下落效果。
【实例代码】
<HTML> <HEAD> <TITLE>黑客帝国</TITLE> <meta http-equiv="Content-Type" content="text/html;charset=gb2312"> </HEAD> <style type="text/css"> body { overflow:hidden; margin:0; background-color:#000000; font-family:宋体; } DIV.#heike { overflow:hidden; position:relative; top:5%; width:90%; height:90%; border-style:solid; border-width:1; border-color:#009900; } </style> <script language="javascript"> var strCount; var str; var Color; var Font; var sLine = "W<br>W<br>W<br>.<br>B<br>a<br>i<br>D<br>u<br>.<br>C<br>O<br>M"; function OnLoad() { strCount = 40; str = []; Color = []; Font = []; Color[0] = "#002211";//文字的颜色 Color[1] = "#003311"; Color[2] = "#005511"; Color[3] = "#008811"; Color[4] = "#00BB99"; Color[5] = "#114411"; Color[6] = "#335566"; Color[7] = "#668899"; Color[8] = "#99BBAA"; Color[9] = "#CECECC"; Font[0] = "10px"; //文字的大小 Font[1] = "12px"; Font[2] = "14px"; Font[3] = "16px"; Font[4] = "18px"; setTimeout("strik()",50); } function strik() { for(var i=0;i<strCount;i++) { if(typeof(str[i]) != "undefined") //如果字符串存在 { if(str[i]["Carch"].style.pixelTop > heike.clientHeight) { str[i]["Carch"].outerHTML = ""; delete str[i]["Level"];//删除数组元素 delete str[i]["Speed"]; delete str[i]["Carch"]; delete str[i]; } else { str[i]["Carch"].style.pixelTop += str[i]["Speed"]; } } else if(Math.random()<0.25) //随机小数 { str[i] = new Array(); str[i]["Level"] = Math.round(Math.random()*4); str[i]["Speed"] = (Math.round(Math.random()*str[i]["Level"])<<2)+10; document.all["heike"].insertAdjacentHTML("AfterBegin","<span id='SPAN_"+i+"'>"+sLine+"</span>"); str[i]["Carch"] = document.all["SPAN_"+i]; str[i]["Carch"].style.fontSize = Font[str[i]["Level"]]; //字体 str[i]["Carch"].style.position = "absolute"; //位置 str[i]["Carch"].style.pixelLeft = Math.round(Math.random()*heike.clientWidth); //x坐标 str[i]["Carch"].style.pixelTop = -str[i]["Carch"].offsetHeight; //y坐标 str[i]["Carch"].style.color = Color[str[i]["Level"]+5]; //颜色 str[i]["Carch"].style.filter = "glow(Color="+Color[str[i]["Level"]]+",Strength=5)";//滤镜效果 str[i]["Carch"].style.zIndex = str[i]["Level"]; //z-Index } } setTimeout("strik()",50); } </script> <BODY onload="OnLoad()"> <table width="100%" height="100%" border="0" cellspacing="0" cellpadding="0"> <tr><td align="center" height="100%"><div id="heike"></div></td></tr> <tr><td align="center" style="padding:5;font-size:9pt;color:#FFFFFF;">使用 IE 6.0 以上版本或以 IE 为核心的浏览器浏览本页,1024*768分辨率为佳</td></tr> </table> </BODY> </HTML>
【运行效果】
【难点剖析】
本例的重点是对颜色和速度的随机设置。JavaScript中的“Math”对象用来提供数学运算,其中“Math random”用来获取一个0到1之问的随机数。“Math.round”是采
用四舍五入方式取得最接近的整数。代码中使用了两维数组,“delete”方法用来删除数组中的元索。
【源码下载】