mootools写的函数ie6报错，为什么？
mootools写的函数ie6报错，为什么？
demo地址：http://www.my-demo.info/question/blur.html
<!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><title>page title</title><meta http-equiv="Content-Type" content="text/html; charset=utf-8" /><script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/mootools/1.4.5/mootools-yui-compressed.js"></script><script type="text/javascript">function update_shopping_cart(){ var form=document.getElementById('shopping_cart_form'); if(typeof form !='undefined'){ var inputs=form.getElements('input[name=cart_quantity[]]'); inputs.addEvent("click",function (){ this.store("old_value",this.value); }); inputs.addEvent('blur', function (){ if(this.value != this.retrieve("old_value")){ form.submit(); } }); }}window.addEvent("domready",function(){ update_shopping_cart();});</script></head><body> <form action="#" id="shopping_cart_form"> <input type="text" size="4" value="1" name="cart_quantity[]"> <input type="text" size="4" value="2" name="cart_quantity[]"> </form></body></html>var form=$('shopping_cart_form');