​x
 
<!DOCTYPE html>
<html>
<head>
<style> 
#main {
  width: 350px;
  height: 100px;
  border: 1px solid #c3c3c3;
  display: flex;
}
​
#main div:nth-of-type(1) {flex-grow: 1;}
#main div:nth-of-type(2) {flex-grow: 1;}
#main div:nth-of-type(3) {flex-grow: 1;}
</style>
</head>
<body>
​
<div id="main">
  <div style="background-color:coral;"></div>
  <div style="background-color:lightblue;" id="myBlueDiv"></div>
  <div style="background-color:khaki;"></div>
</div>
​
<p>请点击“试一试”按钮，将蓝色 div 元素的 flexGrow 属性值设置为 “5”。</p>
​
<button onclick="myFunction()">试一试</button>
​
<p><b>注释：</b>Internet Explorer 10 及更早版本不支持 flexGrow 属性。</p>
​
<script>
function myFunction() {
  document.getElementById("myBlueDiv").style.flexGrow = "5";
}
</script>
​
</body>
</html>
​