需要JS帮助，
我需要根据输入字段中输入的“年份”更改输入文本。
并在更改“要显示的年份”时，禁用不必要的收入/资产字段。
<!DOCTYPE html>
<html>
<head>
<title>title</title>
<script type="text/javascript">
window.onload=function() {
// On "year" change, validate it and cahnge the text befor the input fields.
var year = document.getElementsByName("year");
year.onclick=function() {
this.year0_text.value = year[this.value];
this.year1_text.value = year[this.value]+1;
this.year2_text.value = year[this.value]+2;
}
// and on "years" change, disable the unnecessary income/assets fields.
}
</script>
</head>
<body>
<form name="ar" action="." method="post">
Year:<br />
<input type="number" name="year" value="2011"><br />
<br />
Years to Show:<br />
<input type="radio" name="years" value="0.5">first period (not full year)<br />
<input type="radio" name="years" value="1">1 year<br />
<input type="radio" name="years" value="2">2 years<br />
<input type="radio" name="years" value="3">3 years<br />
<br />
Income:<br />
<span class="year0_text">20XX-0</span> <input type="number" name="year0_income" value="0"><br />
<span class="year1_text">20XX-1</span> <input type="number" name="year1_income" value="0"><br />
<span class="year2_text">20XX-2</span> <input type="number" name="year2_income" value="0"><br />
<br />
Assets:<br />
<span class="year0_text">20XX-0</span> <input type="number" name="year0_assets" value="0"><br />
<span class="year1_text">20XX-1</span> <input type="number" name="year1_assets" value="0"><br />
<span class="year2_text">20XX-2</span> <input type="number" name="year2_assets" value="0"><br />
</form>
</body>
</html>
DEMO - http://jsfiddle.net/92GaE/2/