❶ js制作简单的书店结算小程序 求大神解答

<!DOCTYPEhtml>
<html>
<head>
	<metahttp-equiv="Content-Type"content="text/html;charset=UTF-8">
	<style>
		{
			margin:0auto;
			width:800px;
		}	
		legend{
			color:red;
		}
		table{
			margin:0auto;
			width:400px;
			border-collapse:collapse;
		}
		td{
			border:1pxsolidgray;
		}
	</style>
	<title>第三题</title>
	<script>
		varShop=function(xm,mc,sl,dj,fs){
			this.xm=xm;
			this.mc=mc;
			this.sl=sl;
			this.dj=dj;
			this.fs=fs;
		};
		Shop.prototype.toString=function(){
			return("客户姓名："+this.xm
				+"
商品名称："+this.mc
				+"
购买数量："+this.sl
				+"
购买单价："+this.dj+"元"
				+"
邮购方式："+this.fs
				+"
总价："+this.sl*this.dj+"元");
		};
		varbuy=function(fm){
			varxm=fm.xm.value.replace(/^s+|s+$/,"");
			varmc=fm.mc.value;
			varsl=fm.sl.value.replace(/D/g,"");
			vardj=fm.dj.value;
			varfs=fm.fs.value;
			if(xm==""){
				alert("填写好客户姓名！");
				fm.xm.focus();
				returnfalse;
			}elseif(sl==""){
				alert("填写好购买数量！");
				fm.sl.focus();
				fm.sl.select();
				returnfalse;
			}elseif(dj==""){
				alert("填写好购买单价！");
				fm.dj.focus();
				returnfalse;
			}
			varsp=newShop(xm,mc,sl,dj,fs);
			alert(sp);
			returntrue;
		};
		onload=function(){
			vararr=[26.0,30,22];
			fm.mc.onchange=function(){
				fm.dj.value=arr[this.selectedIndex].toFixed(1);
			};
			fm.dj.value=arr[0].toFixed(1);
		};
	</script>
</head>
<body>
	<fieldset>
		<legend>
			网上购物>>>网上商店
		</legend>
		<formname="fm"onsubmit="returnbuy(this);">
			<table>
			<tr>
				<td>客户姓名：</td>
				<td>
					<inputtype="text"name="xm"/>
				</td>
			</tr>
			<tr>
			<td>商品名称：</td>
				<td>
					<selectname="mc">
						<option>高等数学</option>
						<option>汇编语言</option>
						<option>JavaScript编程</option>
					</select>
				</td>
			</tr>
			<tr>
				<td>购买数量：</td>
				<td><inputtype="text"name="sl"/></td>
			</tr>
			<tr>
				<td>购买单价：</td>
				<td>
					<inputname="dj"type="text"readonly="readonly"/>
				</td>
			</tr>
			<tr>
				<td>邮购方式：</td>
				<td>
			<label><inputtype="radio"name="fs"value="平邮"checked="true"/>平邮</label>
			<label><inputtype="radio"name="fs"value="挂号"/>挂号</label>
			<label><inputtype="radio"name="fs"value="EMS"/>EMS</label>
				</td>
			</tr>
			<tr>
				<tdcolspan=2style="text-align:center;">
					<inputtype="submit"value="现在购买"/>
					<inputtype="reset"value="重写订单"/>
				</td>
			</tr>
		</table>
		</form>
	</fieldset>
</body>
</html>