// JavaScript Document
$.extend({   
   cover:{   
	   show:function(){   
		   $.cover.hide();   
		   var str="<div id='cover' style='position:absolute;background-color: #666;"  
			   str+="width:100%;";   
			   str+="height:"+(document.body.offsetHeight +document.body.scrollTop)+"px;"; 
			   str+="opacity:0.5;filter:alpha(opacity=50);"  
			   str+="top:0;left:0;z-index=10'></div>";   
		   $(document.body).append(str);
		   $("html").css('overflow-y','hidden');
	   },   
	   hide:function(){  
		   $("#cover").remove();   
		   $("html").css('overflow-y','scroll');
	   }   
   }   
});

//验证邮箱地址
function checkEmail(str){
	var re =  /^([a-zA-Z0-9]+[_|\-|\.]?)*[a-zA-Z0-9]+@([a-zA-Z0-9]+[_|\-|\.]?)*[a-zA-Z0-9]+\.[a-zA-Z]{2,3}$/;
	var result = re.test(str);
	return result;
}
//数字+英文+下划线+点
function checkCharStyle_01(str){
		var re = /^([a-zA-Z0-9]|(_)|\.)*$/;
		var result = re.test(str);
	return result;
}