代码如下:
$("#dialog").dialog({
bgiframe: true,
autoOpen: false,
position: [PosX, PosY], //alert 出来为：" , "(不含双引号)，或者报错，不知什么原因。
height: 300,
modal: true,
buttons: {
'创建新账号': function() {
var bValid = true;
allFields.removeClass('ui-state-error');

bValid = bValid && checkLength(name, "username", 3, 16);
bValid = bValid && checkLength(email, "email", 6, 80);
bValid = bValid && checkLength(password, "password", 5, 16);

bValid = bValid && checkRegexp(name, /^[a-z]([0-9a-z_])+$/i, "Username may consist of a-z, 0-9, underscores, begin with a letter.");
// From jquery.validate.js (by joern), contributed by Scott Gonzalez: http://projects.scottsplayground.com/email_address_validation/
bValid = bValid && checkRegexp(email, /^((([a-z]|d|[!#$%&'*+-/=？^_`{|}~]|[u00A0-uD7FFuF900-uFDCFuFDF0-uFFEF])+(.([a-z]|d|[!#$%&'*+-/=？^_`{|}~]|[u00A0-uD7FFuF900-uFDCFuFDF0-uFFEF])+)*)|((x22)((((x20|x09)*(x0dx0a))？(x20|x09)+)？(([x01-x08x0bx0cx0e-x1fx7f]|x21|[x23-x5b]|[x5d-x7e]|[u00A0-uD7FFuF900-uFDCFuFDF0-uFFEF])|(\([x01-x09x0bx0cx0d-x7f]|[u00A0-uD7FFuF900-uFDCFuFDF0-uFFEF]))))*(((x20|x09)*(x0dx0a))？(x20|x09)+)？(x22)))@((([a-z]|d|[u00A0-uD7FFuF900-uFDCFuFDF0-uFFEF])|(([a-z]|d|[u00A0-uD7FFuF900-uFDCFuFDF0-uFFEF])([a-z]|d|-|.|_|~|[u00A0-uD7FFuF900-uFDCFuFDF0-uFFEF])*([a-z]|d|[u00A0-uD7FFuF900-uFDCFuFDF0-uFFEF]))).)+(([a-z]|[u00A0-uD7FFuF900-uFDCFuFDF0-uFFEF])|(([a-z]|[u00A0-uD7FFuF900-uFDCFuFDF0-uFFEF])([a-z]|d|-|.|_|~|[u00A0-uD7FFuF900-uFDCFuFDF0-uFFEF])*([a-z]|[u00A0-uD7FFuF900-uFDCFuFDF0-uFFEF]))).？$/i, "eg. ui@jquery.com");
bValid = bValid && checkRegexp(password, /^([0-9a-zA-Z])+$/, "Password field only allow : a-z 0-9");

if (bValid) {
$('#users tbody').append('tr' +
'td' + name.val() + '/td' +
'td' + email.val() + '/td' +
'td' + password.val() + '/td' +
'/tr');
$(this).dialog('close');
};
},
取消: function() {
$(this).dialog('close');
}
},

close: function() {
allFields.val('').removeClass('ui-state-error');
}
});

后来参考"wind"的为jquery.ui.dialog 增加“自动记住关闭时的位置”的功能。,在他的建议下，完全照葫芦画瓢写了个jquery.ui.dialog的重载方法,实现在鼠标当前位置打开dialog

代码如下
代码如下:
///////////////////////////////////
//指定 jquery.ui.dialog打开时的位置
///////////////////////////////////
(function($) {
var originOpen = $.ui.dialog.prototype.open
$.ui.dialog.prototype.open = function() {
//var event= window.event || arguments.callee.caller.arguments[0];
//var event = event || window.event;
var event = getEvent();
//alert(event) // ie 和 ff下，都显示 "[object]"
var PosX = 0;
var PosY = 0;
if (event.pageX || event.pageY) {
PosX = event.pageX;
PosY = event.pageY;
}
else {
PosX = event.clientX + document.body.scrollLeft - document.body.clientLeft;
PosY = event.clientY + document.body.scrollTop - document.body.clientTop;
};
this.options.position = [PosX, PosY];
//alert(this.options.position);
originOpen.apply(this, arguments);
};

function getEvent() { //同时兼容ie和ff的写法
if (document.all) return window.event;
func = getEvent.caller;
while (func != null) {
var arg0 = func.arguments[0];
if (arg0) {
if ((arg0.constructor == Event || arg0.constructor == MouseEvent)
|| (typeof (arg0) == "object" && arg0.preventDefault && arg0.stopPropagation)) {
return arg0;
}
}
func = func.caller;
}
return null;
}
})(jQuery);

再次感谢"wind"。感谢 jww测试。（已兼容ie7,8,firefox3.5,chrome4）