Positioning Context Menu

问题

I'm trying to position a custom context menu with jQuery.
The first time it appears at the right position (mouse coordinates), but then the current position is being summed up with the new position, so that the menu disappears from the screen.
Here is the JavaScript:

<script>
$(function(){
    $('#box').hide();

    $(document).bind("contextmenu", function(e) {
        $("#box").offset({left:e.pageX, top:e.pageY});
        $('#box').show();
        e.preventDefault();
    });

    $(document).bind("click", function(e) {
        $('#box').hide();
    });
    $('#box').bind("click", function(e) {
        $('#box').hide();
    });
});
</script>

回答1:

Don't use offset method, try css instead, positioning context menu absolutely:

$("#box").css({left:e.pageX, top:e.pageY});

CSS:

#box {
    ...
    position: absolute;
}

http://jsfiddle.net/smxLk/

回答2:

The problem is that when you right click then left click elsewhere and then right click again, the position is incorrect.

The root of the problem is that you set the offset before showing the element. It appears that it confuses jQuery if the element is set to display:none and then its offset is changed.

To fix the problem you need to switch the show and the offset lines in your code:

$(document).bind("contextmenu", function(e) {
    $("#box").offset({left:e.pageX, top:e.pageY});
    $('#box').show();
    e.preventDefault();
});

becomes

$(document).bind("contextmenu", function(e) {
    $('#box').show();
    $("#box").offset({left:e.pageX, top:e.pageY});
    e.preventDefault();
});

Demo
and
Source

回答3:

Try position: fixed; with position of context menu changes based on following condition -

var windowHeight = $(window).height()/2;
var windowWidth = $(window).width()/2;
if(e.clientY > windowHeight && e.clientX <= windowWidth) {
  $("#contextMenuContainer").css("left", e.clientX);
  $("#contextMenuContainer").css("bottom", $(window).height()-e.clientY);
  $("#contextMenuContainer").css("right", "auto");
  $("#contextMenuContainer").css("top", "auto");
} else if(e.clientY > windowHeight && e.clientX > windowWidth) {
  $("#contextMenuContainer").css("right", $(window).width()-e.clientX);
  $("#contextMenuContainer").css("bottom", $(window).height()-e.clientY);
  $("#contextMenuContainer").css("left", "auto");
  $("#contextMenuContainer").css("top", "auto");
} else if(e.clientY <= windowHeight && e.clientX <= windowWidth) {
  $("#contextMenuContainer").css("left", e.clientX);
  $("#contextMenuContainer").css("top", e.clientY);
  $("#contextMenuContainer").css("right", "auto");
  $("#contextMenuContainer").css("bottom", "auto");
} else {
  $("#contextMenuContainer").css("right", $(window).width()-e.clientX);
  $("#contextMenuContainer").css("top", e.clientY);
  $("#contextMenuContainer").css("left", "auto");
  $("#contextMenuContainer").css("bottom", "auto");
}

http://jsfiddle.net/AkshayBandivadekar/zakn7Lwb/14/

来源：https://stackoverflow.com/questions/15795253/positioning-context-menu

标签

javascript

jquery

contextmenu