function btn_move(el, mouseLeft, mouseTop){ var leftRnd = (Math.random()-0.5)*20; var topRnd = (Math.random()-0.5)*20; var btnLeft = mouseLeft+(leftRnd>0?100:-100)+leftRnd; var btnTop = mouseTop+(topRnd>0?30:-30)+topRnd; btnLeft = btnLeft<100?(btnLeft+window.innerWidth-200):(btnLeft>window.innerWidth-100?btnLeft-window.innerWidth+200:btnLeft); btnTop = btnTop<100?( btnTop+window.innerHeight-200):(btnTop>window.innerHeight-100?btnTop-window.innerHeight+200:btnTop); el.style.position = 'fixed'; el.style.left = btnLeft+'px'; el.style.top = btnTop+'px'; } function over_btn(e){ if(!e){ e = window.event; } btn_move(this, e.clientX, e.clientY); } document.getElementById('gbqfba').onmouseover = over_btn;