<!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.jb51.net/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 onclick="numDec()">-</span> <input type="text" id="quantity" /> <span onclick="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>