Strange underscore param in remote links

问题

I use Rails3, JQuery and will_paginate gem to make remote pagination links. Known solution for this is:

$('.pagination a').live('click',function (){
  $.getScript(this.href);
  return false;
});

With this code I get links like: http://localhost:3000/products?_=1300468875819&page=1 or http://localhost:3000/products?_=1300468887024&page=2. So the little question is: what is this strange param _=1300468887024 (looks like Unix-time). What is its purpose? As I know this can cause some problems with search crawlers.

UPD: The solution is described here.

回答1:

it's a cache buster. It's also used in development mode, so to avoid getting an old request from the browser cache.

(unfortunately, all the explanations I found are realated to advertisement :S)

回答2:

This is a simple solution if you don't mind removing it for all requests:

jQuery.ajaxSetup({ cache: true });

回答3:

Another solution would be to extend jQuery's getScript function as per the documentation:

jQuery.cachedScript = function(url, options) {
  options = $.extend(options || {}, {
    dataType: "script",
    cache: true,
    url: url
  });
  return jQuery.ajax(options);
};

This way, only the ajax calls using this new method will use the cache. On the other hand, if you used the ajaxSetup method, all your ajax calls would cache by default since ajaxSetup sets the cache property globally.

Now you can use $.cachedScript(location.href); instead of $.getScript(this.href);.

来源：https://stackoverflow.com/questions/5355667/strange-underscore-param-in-remote-links