Html – Can you take a “screenshot” of the page using Canvas

Using

$("a").attr("href", "http://www.google.com/")

will modify the href of all hyperlinks to point to Google. You probably want a somewhat more refined selector though. For instance, if you have a mix of link source (hyperlink) and link target (a.k.a. "anchor") anchor tags:

<a name="MyLinks"></a>
<a href="http://www.codeproject.com/">The CodeProject</a>

...Then you probably don't want to accidentally add href attributes to them. For safety then, we can specify that our selector will only match <a> tags with an existing href attribute:

$("a[href]") //...

Of course, you'll probably have something more interesting in mind. If you want to match an anchor with a specific existing href, you might use something like this:

$("a[href='http://www.google.com/']").attr('href', 'http://www.live.com/')

This will find links where the href exactly matches the string http://www.google.com/. A more involved task might be matching, then updating only part of the href:

$("a[href^='http://stackoverflow.com']")
   .each(function()
   { 
      this.href = this.href.replace(/^http:\/\/beta\.stackoverflow\.com/, 
         "http://stackoverflow.com");
   });

The first part selects only links where the href starts with http://stackoverflow.com. Then, a function is defined that uses a simple regular expression to replace this part of the URL with a new one. Note the flexibility this gives you - any sort of modification to the link could be done here.

This can now be done in Chrome, Safari, Firefox 4+, and Internet Explorer 10pp4+!

See this question's answer for more information: Updating address bar with new URL without hash or reloading the page

Example:

 function processAjaxData(response, urlPath){
     document.getElementById("content").innerHTML = response.html;
     document.title = response.pageTitle;
     window.history.pushState({"html":response.html,"pageTitle":response.pageTitle},"", urlPath);
 }

You can then use window.onpopstate to detect the back/forward button navigation:

window.onpopstate = function(e){
    if(e.state){
        document.getElementById("content").innerHTML = e.state.html;
        document.title = e.state.pageTitle;
    }
};

For a more in-depth look at manipulating browser history, see this MDN article.