就是清除之前設置所有的樣式，arr.removeAttribute('style')

????<input?type="button"?value="改變顏色"?onclick="co()">
????<input?type="button"?value="改變寬高"??onclick="wd()">
????<input?type="button"?value="隱藏內容"??onclick="cn()">
????<input?type="button"?value="顯示內容"??onclick="cx()">
????<input?type="button"?value="取消設置"??onclick="qv()">
??</form>
<script>
????var?arr=document.getElementById("txt");
????function?co()?{
????????arr.style.color='red';
????????arr.style.backgroundColor='blue';
????}
????function?wd()?{
????????arr.style.width="500px";
????????arr.style.height="800px";
????}
????function?cn()?{
????????arr.style.display='none';
????}
????function?cx()?{
????????arr.style.display='block';
????}
????function?qv()?{
????????var?open=confirm("是否取消設置？")
????????if(open==true){
????????arr.removeAttribute('style')

????????}
????}