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Traditionally webpages required reloading to update their content. For web-based email this meant that users had to manually reload their inbox to check and see if they had new mail. This had huge drawbacks: it was slow and it required user input. When the user reloaded their inbox, the server had to reconstruct the entire web page and resend all of the HTML, CSS, JavaScript, as well as the user's email. This was hugely inefficient. Ideally, the server should only have to send the user's new messages, not the entire page. By 2003, all the major browsers solved this issue by adopting the XMLHttpRequest (XHR) object, allowing browsers to communicate with the server without requiring a page reload.