JavaScript实现输入框默认值同步与实时同步

<input type="text" id="price2" value="333"/>
<input type="text" id="trueprice" value="" />

<script type="text/javascript">
document.getElementById("price2").onkeyup = function() {
document.getElementById("trueprice").value = this.value;
}
</script>

<!DOCTYPE HTML>

<html>

<head>

<meta http-equiv="content-type" content="text/html;charset=utf-8">

<title>Test</title>

</head>

<body>

<input type="text" id="price2" value="333" onkeyup="test(this.value);"/>

<input type="text" id="trueprice" value="" />

<script type="text/javascript">

var price2 = document.getElementById("price2").value;

document.getElementById("trueprice").value = price2;

function test (defaultVal) {

document.getElementById("trueprice").value = defaultVal;

}

</script>

</body>

</html>