var my_key="key_my_login";
$(document).ready(function () {
    $("#username").unbind("focus").bind("focus", function () {
        var myname=getCookie(my_key);
        $("#username").val(myname);
    })
    $("#username").unbind("blur").bind("blur", function () {
        var myname=$("#username").val();
        if(myname!="")
	{
	   setCookie(my_key,myname);
	}
        
    })
})

//写cookies 
function setCookie(name,value) 
{ 
    var Days = 100; 
    var exp = new Date(); 
    exp.setTime(exp.getTime() + Days*24*60*60*1000); 
    document.cookie = name + "="+ escape (value) + ";expires=" + exp.toGMTString(); 
} 

//读取cookies 
function getCookie(name) 
{ 
    var arr,reg=new RegExp("(^| )"+name+"=([^;]*)(;|$)");
    if(arr=document.cookie.match(reg))
        return unescape(arr[2]); 
    else 
        return null; 
}