js method to achieve animation effects similar to animate in jquery

js method to achieve animation effects similar to animate in jquery_javascript skills

WBOY

Release： 2016-05-16 16:05:00

Original

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The example in this article describes how js can achieve animation effects similar to animate in jquery. Share it with everyone for your reference. The specific analysis is as follows:

This example can achieve the effect of moving the mouse up, first changing the width, then changing the height, and finally changing the transparency, moving the mouse out, and then changing back again.

Point 1:

startrun(obj,attr,target,fn)
box.onmouseover = function(){
startrun(box,"width",200,function(){
startrun(box,"height",200,function(){
startrun(box,"opacity","100")
});
});
}

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As above, functions can also be used as parameters, which can achieve the effect of executing an action first and then executing an action.

Point 2:

if(cur == target){
clearInterval(obj.timer);
if(fn){
fn();
}
}

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When the movement reaches the target point, turn off the timer, and then you can execute the new function.

Finally, add the code:

<!DOCTYPE html>
<html>
<head>
<meta charset="gb2312" />
<title>无标题文档</title>
<style>
<!--
body{margin:0; padding:0; font:12px/1.5 arial;}
#box{width:100px; height:100px; position:absolute;
background:#06c; left:0;filter:alpha(opacity=30); opacity:0.3;}
-->
</style>
<script>
<!--
function getstyle(obj,name){
 if(obj.currentStyle){
  return obj.currentStyle[name];
 }else{
  return getComputedStyle(obj,false)[name];
 }
}
window.onload = function(){
 var box = document.getElementById("box");
 box.onmouseover = function(){
  startrun(box,"width",200,function(){
   startrun(box,"height",200,function(){
    startrun(box,"opacity","100")
   });
  });
 }
 box.onmouseout = function(){
  startrun(box,"height",100,function(){
   startrun(box,"width",100,function(){
    startrun(box,"opacity","30");
   });
  });
 }
}
function startrun(obj,attr,target,fn){
 clearInterval(obj.timer);
 obj.timer = setInterval(function(){
  var cur = 0;
  if(attr == "opacity"){
   cur = Math.round(parseFloat(getstyle(obj,attr))*100);
  }else{
   cur = parseInt(getstyle(obj,attr));
  }
  var speed = (target-cur)/8;
  speed = speed>0&#63;Math.ceil(speed):Math.floor(speed);
  
  if(cur == target){
   clearInterval(obj.timer);
   if(fn){
    fn();
   }
  }else{
   if(attr == "opacity"){
    obj.style.filter = "alpha(opacity="+(cur+speed)+")";
    obj.style.opacity = (cur+speed)/100;
   }else{
   obj.style[attr] = cur + speed + "px";
   }
  }
 },30)
}
//-->
</script>
</head>
<body>
<div id="box">
</div>
</body>
</html>

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I hope this article will be helpful to everyone’s JavaScript programming design.