第一种方法：

如果使用的提交按钮是button 不是submit 以及服务器控件 可以在ajax返回结果之后document.getElementById('form').submit();

第二种：

function BeginSubmit() {
            var txt = "";
            jQuery.ajax({
                type:"POST",async:false,//是否异步   
                url: "GetTotalAmount.aspx",success:function(result){
                    if (result.text == "false") {
                    DIVAlert('alert','Valor\'s Minimum Order Policy is $25.00.  We welcome you to continue to browse and shop on our website,and thank you for your business!',null,null);
                    return false;
                }
                else {
                    if (validateForm() && GetTotalAmount()) {
                        if (jQuery('[name=outOfStack]').length > 0) {
                            if (!confirm('Out of stock Or offline products will add to backorder,Do you want to submit Order?'))
                                return false;
                        } else {
                            if (!confirm('Do you want to submit Order?'))
                                return false;
                        }
                    } else {
                        return false;
                    }
                    ProcessOrder();
                }
                }
            })

        }