배경을 4개로 둬서 일정시간이 지나면 순서대로 배경이 하나씩 나타나게 하는것인데

</p><p><script></p><p>var image_index = 0</p><p>function changeback() {</p><p><span class="kwd">    var</span><span class="pln"> urlString </span><span class="pun">=</span><span class="pln"> </span><span class="str">'url(./img5/visual_img_'</span><span class="pln"> </span><span class="pun">+</span><span class="pln"> image_index </span><span class="pun">+</span><span class="pln"> </span><span class="str">'.jpg)'</span><span class="pun">;</span></p><p><span class="pun">    ​</span><span class="pln">document</span><span class="pun">.</span><span class="pln">getElementById</span><span class="pun">(back</span><span class="pun">).</span><span class="pln">style</span><span class="pun">.</span><span class="pln">backgroundImage </span><span class="pun">=</span><span class="pln">  urlString</span><span class="pun">;</span></p><p><span class="pun">    ​</span>image_index++;</p><p>    if (image_index == 4) image_index = 0;</p><p>}</p><p>changeback(); //처음 0번째 이미지를 배경으로 
</p><p>setInterval("changeback()", 5000); //5초마다 배경바뀜</p><p></script></p><p>