关于alpha>iTarget的问题想问下大家
<!doctype html> <html> <head> <meta charset="UTF-8"> <title>透明度</title> <style> *{ margin:0;padding:0; } #div{ width:300px;height:200px;background:red;filter:alpha(opacity:30);opacity:0.3; } </style> </head> <script> window.onload=function(){ var onDiv=document.getElementById('div'); onDiv.onmouseover=function(){ startmove(100); } onDiv.onmouseout=function(){ startmove(30); } } var timer=null; alpha=30; function startmove(iTarget){ var onDiv=document.getElementById('div'); clearInterval(timer) timer=setInterval(function(){ var speed=0; if(alpha>iTarget){ speed=-10; }else{ speed=10; } if(alpha==iTarget){ clearInterval(timer); }else{ alpha+=speed; onDiv.style.filter='alpha(opacity:'+alpha+')'; onDiv.style.opacity=alpha/100; } },30) } </script> <body> <p id="div"></p> </body> </html>
老师在讲alpha>iTarget我其实是有点懵的,因为我看了下已经定义了alpha=30,并且iTarget在30-100之间徘徊的,那我应该怎么去理解这句话?