做商城时候，购物车中的商品加一个和减一个用jquery实现的代码，并且保证文本框text只能输入纯数字。
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>js数量加减</title>
<script type="text/javascript" src="http://www.daixiaorui.com/Public/js/jquery.min.js"></script>
<script type="text/javascript">
$(function(){
$("#quantity").keyup(function(){
if(isNaN($(this).val()) || parseInt($(this).val())<1){
$(this).val("1");
$("#totalPrice").html($("#price").val());
return;
}
var total = parseFloat($("#price").val())*parseInt($(this).val());
$("#totalPrice").html(total.toFixed(2));
})
})
/*商品数量+1*/
function numAdd(){
var num_add = parseInt($("#quantity").val())+1;
if($("#quantity").val()==""){
num_add = 1;
}
$("#quantity").val(num_add);
var total = parseFloat($("#price").val())*parseInt($("#quantity").val());
$("#totalPrice").html(total.toFixed(2));
}
/*商品数量-1*/
function numDec(){
var num_dec = parseInt($("#quantity").val())-1;
if(num_dec<1){
//购买数量必须大于或等于1
alert("not lt 1");
}else{
$("#quantity").val(num_dec);
var total = parseFloat($("#price").val())*parseInt($("#quantity").val());
$("#totalPrice").html(total.toFixed(2));
}
}
</script>
</head>
<body>
<p>Quantity: <span οnclick="numDec()">-</span> <input type="text" id="quantity" /> <span οnclick="numAdd()">+</span></p>
<p class="sdsd">Total Price: <span id="totalPrice">28.10</span></p>
<input type="hidden" value="28.1" id="price" /><!--单价-->
</body>
</html>