javascript - Making custom right-click context menus for my web-app

Question

I've a few websites like google-docs and map-quest that have custom drop down menus when you right-click. Somehow they override the browser's behavior of drop-down menu, and I'm now sure exactly how they do it. I found a jQuery plugin that does this, but I'm still curious about a few things:

• How does this work? Is the browser's drop-down menu actually being overridden, or is the effect just simulated? If so, how?
• What does the plugin abstract away? What's going on behind the scenes?
• Is this the only way of achieving this effect?

See several custom-context menus in action

Answer 1

I know this question is very old, but just came up with the same problem and solved it myself, so I'm answering in case anyone finds this through google as I did. I based my solution on @Andrew's one, but basically modified everything afterwards.

EDIT: seeing how popular this has been lately, I decided to update also the styles to make it look more like 2014 and less like windows 95. I fixed the bugs @Quantico and @Trengot spotted so now it's a more solid answer.

EDIT 2: I set it up with StackSnippets as they're a really cool new feature. I leave the good jsfiddle here for reference thought (click on the 4th panel to see them work).

New Stack Snippet:

// JAVASCRIPT (jQuery)

// Trigger action when the contexmenu is about to be shown
$(document).bind("contextmenu", function (event) {
    
    // Avoid the real one
    event.preventDefault();
    
    // Show contextmenu
    $(".custom-menu").finish().toggle(100).
    
    // In the right position (the mouse)
    css({
        top: event.pageY + "px",
        left: event.pageX + "px"
    });
});


// If the document is clicked somewhere
$(document).bind("mousedown", function (e) {
    
    // If the clicked element is not the menu
    if (!$(e.target).parents(".custom-menu").length > 0) {
        
        // Hide it
        $(".custom-menu").hide(100);
    }
});


// If the menu element is clicked
$(".custom-menu li").click(function(){
    
    // This is the triggered action name
    switch($(this).attr("data-action")) {
        
        // A case for each action. Your actions here
        case "first": alert("first"); break;
        case "second": alert("second"); break;
        case "third": alert("third"); break;
    }
  
    // Hide it AFTER the action was triggered
    $(".custom-menu").hide(100);
  });

/* CSS3 */

/* The whole thing */
.custom-menu {
    display: none;
    z-index: 1000;
    position: absolute;
    overflow: hidden;
    border: 1px solid #CCC;
    white-space: nowrap;
    font-family: sans-serif;
    background: #FFF;
    color: #333;
    border-radius: 5px;
    padding: 0;
}

/* Each of the items in the list */
.custom-menu li {
    padding: 8px 12px;
    cursor: pointer;
    list-style-type: none;
    transition: all .3s ease;
    user-select: none;
}

.custom-menu li:hover {
    background-color: #DEF;
}

<!-- HTML -->
<script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/jquery/1.10.1/jquery.js"></script>

<ul class='custom-menu'>
  <li data-action="first">First thing</li>
  <li data-action="second">Second thing</li>
  <li data-action="third">Third thing</li>
</ul>

<!-- Not needed, only for making it clickable on StackOverflow -->
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