$(document).on('click','.caina_span',function(e){
    var block=$('.zan').css('display');
    if($.trim(block)=='block'){
        return false;
    }
   var positionY=e.pageY;
   var positionX=e.pageX;
    $('.zan').css({"top":+(positionY-50)+"px","left":+(positionX-100)+"px","display":"block"});
    $('.caina_span').removeClass('clicked');
    $(this).hide();
})