0
我試圖在屏幕上逐漸顯示文本(如字幕)。例如H ..他..地獄..你好。當我在VS2010中進行調試時,它正在工作!但是當它實際運行時,它會立即顯示整個句子。函數調用函數WEIRD結果
我在每個字母之間做了一定的「延遲」約3秒,所以它會假設需要一段時間,但實際上它會立即顯示一切。
誰是解決這個謎的天才? (請不要給我建議如何創建marquee效果,這不再是問題,現在它只是我和javascript之間的WAR!)我假設它在從函數調用函數時與同步有關?
感謝任何人會幫助我恢復理智。
您可以下載代碼從這裏(VS項目): http://pcgroup.co.il/downloads/misc/function_from_function.zip
或查看在這裏:
<body>
<script type="text/javascript">
//trying to display this source sentence letter by letter:
var source = "hi javascript why are you being such a pain";
var target = "";
var pos = 0;
var mayGoOn = false;
//this function calls another function which suppose to "build" the sentence increasing index using the global var pos (it's even working when following it in debug)
function textticker() {
if (pos < source.length) {
flash();
if (mayGoOn == true) {
pos++;
mayGoOn = false;
document.write(target);
textticker();
}
}
}
function flash() {
//I tried to put returns everywhere assuming that this may solve it probably one of them in not necessary but it doesn't solve it
if (mayGoOn == true) { return; }
while (true) {
var d = new Date();
if (d.getSeconds() % 3 == 0) {
//alert('this suppose to happen only in about every 3 seconds');
target = source.substring(0, pos);
mayGoOn = true;
return;
}
}
}
textticker();
</script>
你應該看看'setTimeout'或'setInterval'功能。 – 2012-01-11 10:35:12
這不是你在同步上下文中做延遲的方式。查找'setTimeout'。 – 2012-01-11 10:35:17
除了塞爾吉奧的回答,這不起作用的原因是循環每秒發生一次以上,所以d.getSeconds()%3 == 0將每3秒成千上萬次。它在調試中起作用的原因是你大量減慢了執行速度。爲了讓它工作,你必須檢查你和上次不一樣。這也將是UI阻塞,所以不是一個好主意。 – mattmanser 2012-01-11 10:42:47