Determining if mouse click happened in left or right half of DIV

A working JS solution:

onClick(e) {
    const clickTarget = e.target;
    const clickTargetWidth = clickTarget.offsetWidth;
    const xCoordInClickTarget = e.clientX - clickTarget.getBoundingClientRect().left;
    if (clickTargetWidth / 2 > xCoordInClickTarget) {
      // clicked left
    } else {
      // clicked right
    }
  }

$("div").click(function(e){
   var pWidth = $(this).innerWidth(); //use .outerWidth() if you want borders
   var pOffset = $(this).offset(); 
   var x = e.pageX - pOffset.left;
    if(pWidth/2 > x)
        $(this).text('left');
    else
        $(this).text('right');
});

DEMO: http://jsfiddle.net/dirtyd77/QRKn7/1/

Hope this helps! Let me know if you have any questions!

This should do it:

$("div").click(function(e){
    var $div = $(this);
    alert(e.pageX >= ($div.offset().left + $div.width()/2) ? 'clicked right' : 'clicked left');
});