过去一天我一直在努力解决这个问题。
我正在尝试制作一些时髦的文本效果，基本上是一种美化的字符串创建。它写一行有点像广告牌，为此我使用了 setTimeout。事情是我想把它放在一个函数中，这样我就可以重用它并在不同的元素上多次调用它。
问题是我需要将文本更新为新文本的一半。为此，我清除了超时，但除非计时器变量超出范围，否则它不会清除。
由于实用性，我真的不能在功能之外拥有它；我不确定它会被调用多少次，在函数外部声明 20 个时间变量感觉不对。
这是在一项上正确运行的代码（多次单击以中断并重新启动）
var t;
function writeStats(str,dest) {
var options = {
"step" : 8, // How many times should the letters be changed
"fps" : 25, // Frames Per Second
"text" : "" // Use this text instead of the contents
}
function randomChar(type){
var pool = "";
if (type == "lowerLetter"){
pool = "abcdefghijklmnopqrstuvwxyz0123456789";
}
else if (type == "upperLetter"){
pool = "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
}
else if (type == "symbol"){
pool = ",.?/\\(^)![]{}*&^%$#'\"";
}
var arr = pool.split('');
return arr[Math.floor(Math.random()*arr.length)];
}
str = str.split('');
var types = [],
letters = [];
for(var i=0;i<str.length;i++){
var ch = str[i];
if(ch == " "){
types[i] = "space";
continue;
}
else if(/[a-z]/.test(ch)){
types[i] = "lowerLetter";
}
else if(/[A-Z]/.test(ch)){
types[i] = "upperLetter";
}
else {
types[i] = "symbol";
}
letters.push(i);
}
clearTimeout(t);
(function shuffle(start){
// This code is run options.fps times per second
// and updates the contents of the page element
var i,
len = letters.length,
strCopy = str.slice(0); // Fresh copy of the string
if(start>len){
return;
}
// All the work gets done here
for(i=Math.max(start,0); i < len; i++){
// The start argument and options.step limit
// the characters we will be working on at once
if( i < start+options.step){
// Generate a random character at this position
strCopy[letters[i]] = randomChar(types[letters[i]]);
}
else {
strCopy[letters[i]] = "";
}
}
//el.text(strCopy.join(""));
el = strCopy.join("");
//console.log(el);
$('.'+dest).text(el);
t = setTimeout(function(){
shuffle(start+1);
},500/options.fps);
})(-options.step);
}
$(document).ready(function(){
$(document).click(function(){
writeStats('this sentence is a great one','t1');
});
});<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js"></script>
<div class="t1"></div>
<div class="t2"></div>如果我将 t 变量带入函数内部，它就不会像以前那样工作：
function writeStats(str,dest) {
var t;
var options = {
"step" : 8, // How many times should the letters be changed
"fps" : 25, // Frames Per Second
"text" : "" // Use this text instead of the contents
}
function randomChar(type){
var pool = "";
if (type == "lowerLetter"){
pool = "abcdefghijklmnopqrstuvwxyz0123456789";
}
else if (type == "upperLetter"){
pool = "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
}
else if (type == "symbol"){
pool = ",.?/\\(^)![]{}*&^%$#'\"";
}
var arr = pool.split('');
return arr[Math.floor(Math.random()*arr.length)];
}
str = str.split('');
var types = [],
letters = [];
for(var i=0;i<str.length;i++){
var ch = str[i];
if(ch == " "){
types[i] = "space";
continue;
}
else if(/[a-z]/.test(ch)){
types[i] = "lowerLetter";
}
else if(/[A-Z]/.test(ch)){
types[i] = "upperLetter";
}
else {
types[i] = "symbol";
}
letters.push(i);
}
clearTimeout(t);
(function shuffle(start){
// This code is run options.fps times per second
// and updates the contents of the page element
var i,
len = letters.length,
strCopy = str.slice(0); // Fresh copy of the string
if(start>len){
return;
}
// All the work gets done here
for(i=Math.max(start,0); i < len; i++){
// The start argument and options.step limit
// the characters we will be working on at once
if( i < start+options.step){
// Generate a random character at this position
strCopy[letters[i]] = randomChar(types[letters[i]]);
}
else {
strCopy[letters[i]] = "";
}
}
//el.text(strCopy.join(""));
el = strCopy.join("");
//console.log(el);
$('.'+dest).text(el);
t = setTimeout(function(){
shuffle(start+1);
},500/options.fps);
})(-options.step);
}
$(document).ready(function(){
$(document).click(function(){
writeStats('this sentence is a great one','t1');
});
});<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js"></script>
<div class="t1"></div>
<div class="t2"></div>如果您运行该代码段，您会发现它不再正常工作。反复单击将显示旧句子仍然存在并且被覆盖。如何在函数内正确清除超时？
我认为“t”变量是每个函数的本地变量，并且会创建一个单独的实例？
谢谢！