How to open link (a href) in new tab instead of loading url on same page?

You can simply use target="_blank" to open new tab and your link it, here is the sample HTML

<a href="URL" target="_blank">Open in new tabs</a>

In the above HTML target attribute specifies where to open the linked document, other values of target attribute is as below

If you want to open a button in new window you can use code below

<button class="btn btn-primary" onClick="window.open('http://www.example.com');">
     Open
</button>

Above answer is correct, but here are multiple version of opening a link in new tab

Using HTML

<a href="example.com" target="_blank">This link will open in new window/tab</a>

Using jQuery

By Selecting all anchor tags which has rel="external", set attribute

<script type="text/javascript">
    $('a[rel="external"]').attr('target', '_blank');
</script>

If you want to create anchor dynamically and open in new tab using Javascript, check https://qawithexperts.com/questions/142/how-to-open-new-tab-using-javascript-or-jquery-and-open-href