<body>
<form>
边长a:<input name="a" type="number" value="3"><br/>
边长b:<input name="b" type="number" value="4"><br/>
边长c:<input name="c" type="number" value="5"><br/>
<input name="calculate" type="button" value="计算周长" onclick="cal(this.form)"><br/>
周长:<input name="s" type="number"><br/>
</form>
<script language="javascript">
function cal(form)
{
var a=form.a.value;
var b=form.b.value;
var c=form.c.value;
form.s.value = a+b+c;
}
</script>
</body>
运行的结果:
这是哪儿的问题?应该怎么解决啊?