setTimeout(code,millisec) 方法用於在指定的毫秒數後調用函數或計算表達式javascript
setInterval(code,millisec) 方法可按照指定的週期(以毫秒計)來調用函數或計算表達式html
區別:setTimeout() 只執行 code 一次。若是要屢次調用,請使用 setInterval() 或者讓 code 自身再次調用 setTimeout()java
setTimeout() 函數實現時鐘的例子函數
<!DOCTYPE html> <html> <head> <meta charset="utf-8"> <title>預備啓動秒錶</title> <script type="text/javascript"> function timedMsg() { var second = document.getElementById("second").value; var minute = document.getElementById("minute").value; var hour = document.getElementById("hour").value; second = parseInt(second); minute = parseInt(minute); hour = parseInt(hour);
var second = second + 1; if(second >59){ second = 0; minute = minute + 1; if(minute > 59){ minute = 0; hour = hour + 1; if(hour>23){ hour = 0; } } } //數據格式處理 if(second < 10){ second = "0" + second; } if(minute < 10){ minute = "0" + minute; } if(hour < 10){ hour = "0" + hour; } document.getElementById('second').value= second; document.getElementById('minute').value= minute; document.getElementById('hour').value= hour; var t = setTimeout("timedMsg();",1000); } </script> </head> <body> <button onclick="timedMsg()">預備啓動秒錶</button> <br> <br> 時<input type="text" name="hour" id="hour" value="00"> 分<input type="text" name="minute" id="minute" value="00"> 秒<input type="text" name="second" id="second" value="00"> </body> </html>