js实现购物车数量的增加与减少，js实现购物车数量的自增与自减
<!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实现购物车数量的增加与减少，js实现购物车数量的自增与自减</title> </head> <body> <center> <table> <tr> <td>1</td> <td><span onclick="changeNum(this,1)" style="cursor:pointer;">+</span><input type="text" value="" onblur="checknum(this)" /><span onclick="changeNum(this,-1)" style="cursor:pointer;">-</span></td> </tr> <tr> <td>2</td> <td><span onclick="changeNum(this,1)" style="cursor:pointer;">+</span><input type="text" value="" onblur="checknum(this)" /><span onclick="changeNum(this,-1)" style="cursor:pointer;">-</span></td> </tr> <tr> <td>3</td> <td><span onclick="changeNum(this,1)" style="cursor:pointer;">+</span><input type="text" value="" onblur="checknum(this)" /><span onclick="changeNum(this,-1)" style="cursor:pointer;">-</span></td> </tr> </table> </center> <script type="text/javascript"> function checknum(obj){ if(obj.value >10){ obj.value = 10; alert('Max 10!'); } } function changeNum(obj,num) { var input = getParent(obj).getElementsByTagName("input"); for(var i=0;i<input.length;i++) { if(input[i].type=="text") { if(input[i].value == "") input[i].value = num; else input[i].value = input[i].value - 0 + num; } if(input[i].value == "-1") input[i].value = 0; if(input[i].value == "11") input[i].value = 10; } } //获取父级对像 function getParent(obj) { if(typeof(obj) != "object"){obj = document.getElementById(obj);} if(obj) return obj.parentElement || obj.parentNode; } </script> </body> </html>