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<!DOCTYPE html>
<html>
<body>
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<h1>JavaScript 数组方法</h1> 
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<h2>unshift()</h2>
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<p>unshift() 方法返回新数组的长度：</p>
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<p id="demo1"></p>
<p id="demo2"></p>
<p id="demo3"></p>
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<script>
var fruits = ["Banana", "Orange", "Apple", "Mango"];
document.getElementById("demo1").innerHTML = fruits;
document.getElementById("demo2").innerHTML = fruits.unshift("Lemon");
document.getElementById("demo3").innerHTML = fruits;
</script>
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<p><b>注释：</b>unshift() 方法在 Internet Explorer 8 及更早版本中无法正常工作，会插入值，但返回值将是 <em>undefined</em>。</p>
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</body>
</html>
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