Access event to call preventdefault from custom function originating from onclick attribute of tag

I have links like this:

<a href="#" onclick="myfunc({a:1, b:'hi'})" />click</a>
<a href="#" onclick="myfunc({a:3, b:'jo'})" />click</a>

And I would like to do a preventDefault() inside myfunc(), because a # will be added in the address bar when clicking on the link (without doing return false; or href='javascript:void(0);')

Is this possible? Can I get the event inside myfunc()

I believe you can pass in event into the function inline which will be the event object for the raised event in W3C compliant browsers (i.e. older versions of IE will still require detection inside of your event handler function to look at window.event).

A quick example.

function sayHi(e) {
   e.preventDefault();
   alert("hi");
}

<a href="http://google.co.uk" onclick="sayHi(event);">Click to say Hi</a>

1. Run it as is and notice that the link does no redirect to Google after the alert.
2. Then, change the event passed into the onclick handler to something else like e, click run, then notice that the redirection does take place after the alert (the result pane goes white, demonstrating a redirect).

The simplest solution simply is:

<a href="#" onclick="event.preventDefault(); myfunc({a:1, b:'hi'});" />click</a>

It's actually a good way of doing cache busting for documents with a fallback for no JS enabled browsers (no cache busting if no JS)

<a onclick="
if(event.preventDefault) event.preventDefault(); else event.returnValue = false;
window.location = 'http://www.domain.com/docs/thingy.pdf?cachebuster=' + 
Math.round(new Date().getTime() / 1000);" 
href="http://www.domain.com/docs/thingy.pdf">

If JavaScript is enabled, it opens the PDF with a cache busting query string, if not it just opens the PDF.

Try this:

<script>
    $("a").click(function(event) {
        event.preventDefault(); 
    });
</script>

<script type="text/javascript">
$('a').click(function(){
   return false;
});
<script>

Add a unique class to the links and a javascript that prevents default on links with this class:

<a href="#" class="prevent-default" 
   onclick="$('.comment .hidden').toggle();">Show comments</a>

<script>
  $(document).ready(function(){

    $("a.prevent-default").click(function(event) {
         event.preventDefault(); 
          });
  });
</script>

Can you not just remove the href attribute from the a tag?

I think when we use onClick we want to do something different than default. So, for all your links with onClick:

$("a[onClick]").on("click", function(e) {
  return e.preventDefault();
});

Simple!

onclick="blabla(); return false"

You can access the event from onclick like this:

<button onclick="yourFunc(event);">go</button>

and at your javascript function, my advice is adding that first line statement as:

function yourFunc(e) {
    e = e ? e : event;
}

then use everywhere e as event variable

Without any JS library or jQuery. To open a nice popup window if possible. Fails safely to normal link open.

<a href="https://acme.com/" onclick="onclick="openNewWindow(event, this.href);">...</a>

And the helper function:

function openNewWindow(event, location) {
  if (event.preventDefault && event.stopImmediatePropagation) { 
    event.preventDefault(); 
    event.stopImmediatePropagation(); 
  } else {
    event.returnValue = false; 
  }
  window.open(location, 'targetWindow', 'toolbar=no,location=no,status=no,menubar=no,scrollbars=yes,resizable=yes,width=800,height=450');
}

e.preventDefault(); from https://developer.mozilla.org/en-US/docs/Web/API/event.preventDefault

Or have return false from your method.