为什么背景颜色闪烁而不是平滑变化？

Question

在这个小代码中，我试图平滑地改变 body 背景的颜色，第一次测试它做了一次最好的工作，在其他测试中颜色随着闪烁而改变。谁知道原因？请帮我解决一下？这违背了我这个节目的目标，但我发现这才是真正的彩色舞蹈。:D

<html>
<body>
 Interval:<input type="number" id="interval" min="0" placeholder="millisecond" value="10" step="10"/>
 Start Point Color: 
  R<input type="number" id="redStart" min="0" max="255" placeholder="ed" value="0"/>
  G<input type="number" id="greenStart" min="0" max="255" placeholder="reen" value="0"/> 
  B<input type="number" id="blueStart" min="0" max="255" placeholder="lue" value="0"/>
 Dancing Color:
  R:<input type="checkbox" id="redDance" checked="true"/>
  G:<input type="checkbox" id="greenDance"/>  
  B:<input type="checkbox" id="blueDance"/>
  <button type="button" id="dance">Dance</button>
  <button type="button" id="stopDance">Stop Dance</button>

 <script type="text/javascript">

 //event for click on dance button
    document.getElementById('dance').onclick = Dancer;
 document.getElementById('stopDance').onclick = stopDancer;

 // this is the dancer function that is responsible for the background color dancing
 function Dancer(){
  var body_color  = document.body.style.backgroundColor;
  var interval_ms = document.getElementById('interval').value;
  var is_red = document.getElementById('redDance').checked;
  var is_green = document.getElementById('greenDance').checked;
  var is_blue = document.getElementById('blueDance').checked;
  var red = document.getElementById('redStart').value;
  var green = document.getElementById('greenStart').value;
  var blue = document.getElementById('blueStart').value;
  //document.body.style.backgroundColor = 'rgb(' + red + ',' + green + ',' + blue + ')';
     document.dancing = setInterval(function(){
   if (is_red && red < 255){
    red++;
    document.getElementById('redStart').value = red;
   }
   if(is_green && green < 255){
    green++;
    document.getElementById('greenStart').value = green;
   }
   if(is_blue && blue < 255){
    blue++;
    document.getElementById('blueStart').value = blue;
   }
   document.body.style.backgroundColor = 'rgb(' + red + ',' + green + ',' + blue + ')';
  },interval_ms
  );
 }
 
 //this is the dancer stop function
 function stopDancer(){
  clearInterval(document.dancing);
 }
  
 </script>
 </body>
 
</html>

Answer 1

试试这个 Fiddle。

我只是在你函数的开头添加了一个clearInterval。现在它不眨眼了。那是你想要的吗？

Answer 2

当您再次启动 Dancer() 并且必须清除时，您的间隔仍然是运行。我添加了 else 颜色完成时的语句，以及所有颜色完成时清除间隔的 if 语句。我还使用 else if 语句扩展了您的代码，以便在未选中时对颜色进行倒计时。

//event for click on dance button
document.getElementById('dance').onclick = Dancer;
document.getElementById('stopDance').onclick = stopDancer;

// this is the dancer function that is responsible for the background color dancing
function Dancer(){
  clearInterval(document.dancing);
  var body_color  = document.body.style.backgroundColor;
  var interval_ms = document.getElementById('interval').value;
  var is_red = document.getElementById('redDance').checked;
  var is_green = document.getElementById('greenDance').checked;
  var is_blue = document.getElementById('blueDance').checked;
  var red = document.getElementById('redStart').value;
  var green = document.getElementById('greenStart').value;
  var blue = document.getElementById('blueStart').value;
  var redDone = false;
  var greenDone = false;
  var blueDone = false;
  document.dancing = setInterval(function(){
    if (is_red && red < 255){
      red++;
      document.getElementById('redStart').value = red;
    }
    else if (!is_red && red > 0){
      red--;
      document.getElementById('redStart').value = red;
    }
    else {
      redDone = true;
    }
    if(is_green && green < 255){
      green++;
      document.getElementById('greenStart').value = green;
    }
    else if(!is_green && green > 0){
      green--;
      document.getElementById('greenStart').value = green;
    }
    else {
      greenDone = true;
    }
    if(is_blue && blue < 255){
      blue++;
      document.getElementById('blueStart').value = blue;
    }
    else if(!is_blue && blue > 0){
      blue--;
      document.getElementById('blueStart').value = blue;
    }
    else {
      blueDone = true;
    }
    document.body.style.backgroundColor = 'rgb(' + red + ',' + green + ',' + blue + ')';
    if(redDone && greenDone && blueDone){
      clearInterval(document.dancing);
    }
  },interval_ms
                                );
}

//this is the dancer stop function
function stopDancer(){
  clearInterval(document.dancing);
}

Interval:<input type="number" id="interval" min="0" placeholder="millisecond" value="10" step="10"/>
Start Point Color: 
R<input type="number" id="redStart" min="0" max="255" placeholder="ed" value="0"/>
G<input type="number" id="greenStart" min="0" max="255" placeholder="reen" value="0"/> 
B<input type="number" id="blueStart" min="0" max="255" placeholder="lue" value="0"/>
Dancing Color:
R:<input type="checkbox" id="redDance" checked="true"/>
G:<input type="checkbox" id="greenDance"/>  
B:<input type="checkbox" id="blueDance"/>
<button type="button" id="dance">Dance</button>
<button type="button" id="stopDance">Stop Dance</button>

为什么背景颜色闪烁而不是平滑变化？

Why the background colour blinks instead of smooth changing?

html

javascript

css

background-color