backbone.js history 里的 pushState 究竟是什么含义？

Question

pushStatesupportexistsonapurelyopt-inbasisinBackbone.Olderbrowsersthatdon'tsupportpushStatewillcontinuetousehash-basedURLfragments,andifahashURLisvisitedbyapushState-capablebrowser,itwillbetransparentlyupgradedtothetrueURL.NotethatusingrealURLsrequiresyourwebservertobeabletocorrectlyrenderthosepages,soback-endchangesarerequiredaswell.Forexample,ifyouhavearouteof/documents/100,yourwebservermustbeabletoservethatpage,ifthebrowservisitsthatURLdirectly.Forfullsearch-enginecrawlability,it'sbesttohavetheservergeneratethecompleteHTMLforthepage...butifit'sawebapplication,justrenderingthesamecontentyouwouldhavefortherootURL,andfillingintherestwithBackboneViewsandJavaScriptworksfine.
看不太懂这一段，能举一个例子吗？

Answer 1

自问自答一下吧，之前旧的浏览器只能通过hashchange来判断单页app地址的变化，而由于html5historyapi的出现，允许通过/path这样的模式来渲染页面，这种模式就叫做pushState，pushState设为true意味可以采用这种模式。在backbone里面，会判断浏览器对historyapi的支持，不支持的浏览器自动降格为hashchange的方式来切换页面。