jQuery: Move element by relative value

Assuming your element has the id 'myElement':

$('#myElement').css(
{
  'position': 'relative',
  'left': '-10px'
});

Here is a quick example using jQuery:

$("#el").css({
    left: $("#el").position().left - 10 + "px"
});

Note: the element that you want to move must either be positioned absolutely or relatively.