JavaScript實現元素屬性的緩沖變化
阿新 • • 發佈：2017-08-25
timer 實例 span r+ mar script char css return
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今天給大家分享一個用JavaScript實現
元素的屬性緩沖變化效果，代碼如下：
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1 //獲取樣式 2 function getStyle( obj, attr ){ //封裝的獲取元素樣式的函數; 3 4 if(obj.currentStyle){ 5 6 return obj.currentStyle[attr]; 7 8}else{ 9 10 return getComputedStyle(obj,false)[attr]; 11 } 12 }
1 function Slow_change( obj, attr, tar, fn ){ //opacity範圍為1~100; 2 clearInterval(obj.timer); //清除定時器; 3 obj.timer = setInterval(function(){ 4 let cur = 0; 5 if(attr == ‘opacity‘){ //獲取要改變的樣式;透明度分開來實現;6 cur = parseInt(parseFloat(getStyle(obj,attr))*100); //取整; 7 }else{ 8 cur = parseInt(getStyle(obj,attr)); 9 }; 10 let speed = (tar - cur)/8;//大於1的整數 11 speed = speed > 0 ? Math.ceil(speed) : Math.floor(speed); //根據速度的正負向上和向下取整; 12 if( cur == tar ){13 clearInterval(obj.timer); //達到預定值時清除定時器; 14 if(attr == ‘opacity‘){ 15 obj.style.filter = ‘alpha(opacity:‘+ cur +‘)‘; 16 obj.style.opacity = cur/100; 17 }else{ 18 obj.style[attr] = tar + ‘px‘; 19 } 20 fn && fn(); //調用回調函數; 21 }else{ 22 if(attr == ‘opacity‘){ 23 obj.style.filter = ‘alpha(opacity:‘ + (cur+speed) + ‘)‘; 24 obj.style.opacity = (cur+speed)/100; 25 }else{ 26 obj.style[attr] = cur + speed + ‘px‘; //設置變化後的樣式; 27 } 28 } 29 },30); 30 }
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上面就是封裝好的緩沖變化函數，通過
出入不同的對象和屬性產生不同的緩沖
變化，下面給出一個實例完整的代碼：
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1 <!DOCTYPE html> 2 <html lang="en"> 3 <head> 4 <meta charset="UTF-8"> 5 <title>demo</title> 6 <style type="text/css"> 7 *{ 8 margin:0; 9 padding:0; 10 } 11 #box{ 12 position:absolute; 13 width:100px; 14 height:100px; 15 background:red; 16 border:1px solid black; 17 } 18 </style> 19 <script type="text/javascript"> 20 window.onload = function(){ 21 function getStyle( obj, attr ){ 22 23 if(obj.currentStyle){ 24 25 return obj.currentStyle[attr]; 26 27 }else{ 28 29 return getComputedStyle(obj,false)[attr]; 30 } 31 } 32 33 function Slow_change( obj, attr, tar, fn ){ 34 clearInterval(obj.timer); 35 obj.timer = setInterval(function(){ 36 let cur = 0; 37 if(attr == ‘opacity‘){ 38 cur = parseInt(parseFloat(getStyle(obj,attr))*100); 39 }else{ 40 cur = parseInt(getStyle(obj,attr)); 41 }; 42 let speed = (tar - cur)/8; 43 speed = speed > 0 ? Math.ceil(speed) : Math.floor(speed); 44 if( cur == tar ){ 45 clearInterval(obj.timer); 46 if(attr == ‘opacity‘){ 47 obj.style.filter = ‘alpha(opacity:‘+ cur +‘)‘; 48 obj.style.opacity = cur/100; 49 }else{ 50 obj.style[attr] = tar + ‘px‘; 51 } 52 fn && fn(); 53 }else{ 54 if(attr == ‘opacity‘){ 55 obj.style.filter = ‘alpha(opacity:‘ + (cur+speed) + ‘)‘; 56 obj.style.opacity = (cur+speed)/100; 57 }else{ 58 obj.style[attr] = cur + speed + ‘px‘; 59 } 60 } 61 },30); 62 } 63 64 var box = document.getElementById(‘box‘); 65 Slow_change( box,‘left‘,500,function(){ 66 alert(1); 67 }); 68 }; 69 </script> 70 </head> 71 <body> 72 <div id="box"></div> 73 </body> 74 </html>
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感謝大家的閱讀
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JavaScript實現元素屬性的緩沖變化