js动画效果之透明度变化

此案例总结的是鼠标移入框内透明度渐变的效果，使用原生js、jquery与css3 3种方法分别实现。照常下面是效果图：

下面是js的实现代码：

window.onload=function(){
                var odiv=document.getElementById("mydiv");              
                odiv.onmousemove=function(){
                    startChange(30);
                }
                odiv.onmouseout=function(){
                    startChange(100);
                }
                var odiv=document.getElementById("mydiv");
            }
            var alpha=30;
            var timer=null;
            function startChange(iTarget){
                clearInterval(timer);
                var odiv=document.getElementById("mydiv");
                timer=setInterval(function(){
                    var speed=0;
                    if(alpha>iTarget){
                        speed=-10;
                    }else{
                        speed=10;
                    }
                    if(alpha==iTarget){
                        clearInterval(timer);
                    }else{
                        alpha+=speed;
                        odiv.style.filter='alpha(opacity:'+alpha+')';
                        odiv.style.opacity=alpha/100;
                    }
                },30);
            }

jquery:

            $(function(){
                $("#mydiv").mouseover(function(){
                    console.log(1);
                $(this).animate({opacity:0.3},1000);
            }).mouseout(function(){
                $(this).animate({opacity:1},1000);
            });
            });

css3

           #mydiv:hover{
                animation:myfirst 1s;
                -moz-animation:myfirst 1s; /* Firefox */
                -webkit-animation:myfirst 1s; /* Safari and Chrome */
                -o-animation:myfirst 1s; /* Opera */
            }
            @keyframes myfirst
            {
            from {opacity:1;}
            to {opacity:0.3;}
            }

            @-moz-keyframes myfirst /* Firefox */
            {
            from {opacity:1;}
            to {opacity:0.3;}
            }

            @-webkit-keyframes myfirst /* Safari and Chrome */
            {
            from {opacity:1;}
            to {opacity:0.3;}
            }

            @-o-keyframes myfirst /* Opera */
            {
            from {opacity:1;}
            to {opacity:0.3;}
            }