preload_img = new Image();
preload_img.src = 'images/common/button_contents_1_2.gif';
preload_img2 = new Image();
preload_img2.src = 'images/common/button_contents_2_2.gif';
preload_img3 = new Image();
preload_img3.src = 'images/common/button_contents_3_2.gif';
preload_img4 = new Image();
preload_img4.src = 'images/common/button_contents_4_2.gif';
preload_img5 = new Image();
preload_img5.src = 'images/common/button_contents_5_2.gif';
preload_img6 = new Image();
preload_img6.src = 'images/common/button_contents_6_2.gif';