关于javascript做跑马灯的效果练习问题
题目是这样做个跑马灯登陆的时候向左转设置两个按钮点击后向相反的方向转动我在做的思路是先写出两个setinterval函数定义一个全局bool然后if判断是向左走向右走可是...
题目是这样 做个跑马灯 登陆的时候向左转 设置两个按钮 点击后向相反的方向转动
我在做的思路是先写出两个setinterval函数 定义一个全局bool 然后if判断是向左走向右走
可是一直调不出来 什么bool变量不能发现，然后我自己就不判定 直接写两个函数 点击按钮后触发 可是又关不掉 越点转的越快 请高手帮助一下
我开始代码
<head>
<title>javascript做简单的跑马灯练习</title>
<script type="text/javascript" language="javascript">
var varBool = false;
function scrollleft() {
varBool = true;
var title = document.title;
var scrollleft = title.charAt(0);
var scrolllast = title.substring(1, title.length);
document.title = scrolllast + scrollleft;
}
function scrollright() {
varBool = false;
var title = document.title;
var scrollright = title.charAt(title.length - 1);
var scrollright1 = title.substring(0, title.length - 1);
document.title = scrollright + scrollright1;
}
function judge() {
if (varBool = ture) {
clearInterval(setInterval("scrollleft()", 500))
setInterval("scrollright()", 500);
}
else {
clearInterval(setInterval("scrollright()", 500))
setInterval("scrollleft()", 500);
}
}
setInterval("scrollleft()",500);
</script>
</head>
<body>
<center>
<input type="button" value="向左转" onclick="judge()"/>
<input type="button" value="向右转" onclick="judge()"/>
</center>
</body>
</html> 展开
我在做的思路是先写出两个setinterval函数 定义一个全局bool 然后if判断是向左走向右走
可是一直调不出来 什么bool变量不能发现，然后我自己就不判定 直接写两个函数 点击按钮后触发 可是又关不掉 越点转的越快 请高手帮助一下
我开始代码
<head>
<title>javascript做简单的跑马灯练习</title>
<script type="text/javascript" language="javascript">
var varBool = false;
function scrollleft() {
varBool = true;
var title = document.title;
var scrollleft = title.charAt(0);
var scrolllast = title.substring(1, title.length);
document.title = scrolllast + scrollleft;
}
function scrollright() {
varBool = false;
var title = document.title;
var scrollright = title.charAt(title.length - 1);
var scrollright1 = title.substring(0, title.length - 1);
document.title = scrollright + scrollright1;
}
function judge() {
if (varBool = ture) {
clearInterval(setInterval("scrollleft()", 500))
setInterval("scrollright()", 500);
}
else {
clearInterval(setInterval("scrollright()", 500))
setInterval("scrollleft()", 500);
}
}
setInterval("scrollleft()",500);
</script>
</head>
<body>
<center>
<input type="button" value="向左转" onclick="judge()"/>
<input type="button" value="向右转" onclick="judge()"/>
</center>
</body>
</html> 展开
1个回答
展开全部
代码有两个问题
1 你把true写成了ture。。
2 你生成了好几个定时器，最开始设置一个，以后每次把它清空重新赋值，这样就不会乱跑了
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>javascript做简单的跑马灯练习</title>
<script type="text/javascript" language="javascript">
var varBool = false;
var run;
function scrollleft() {
varBool = true;
var title = document.title;
var scrollleft = title.charAt(0);
var scrolllast = title.substring(1, title.length);
document.title = scrolllast + scrollleft;
}
function scrollright() {
varBool = false;
var title = document.title;
var scrollright = title.charAt(title.length - 1);
var scrollright1 = title.substring(0, title.length - 1);
document.title = scrollright + scrollright1;
}
function judge() {
if (varBool = true) {
//clearInterval(setInterval("scrollleft()", 500))
clearInterval(run);
run=setInterval("scrollright()", 500);
}
else {
//clearInterval(setInterval("scrollright()", 500))
clearInterval(run);
run=setInterval("scrollleft()", 500);
}
}
run=setInterval("scrollleft()",500);
</script>
</head>
<body>
<center>
<input type="button" value="向左转" onclick="judge()"/>
<input type="button" value="向右转" onclick="judge()"/>
</center>
</body>
</html>
1 你把true写成了ture。。
2 你生成了好几个定时器，最开始设置一个，以后每次把它清空重新赋值，这样就不会乱跑了
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>javascript做简单的跑马灯练习</title>
<script type="text/javascript" language="javascript">
var varBool = false;
var run;
function scrollleft() {
varBool = true;
var title = document.title;
var scrollleft = title.charAt(0);
var scrolllast = title.substring(1, title.length);
document.title = scrolllast + scrollleft;
}
function scrollright() {
varBool = false;
var title = document.title;
var scrollright = title.charAt(title.length - 1);
var scrollright1 = title.substring(0, title.length - 1);
document.title = scrollright + scrollright1;
}
function judge() {
if (varBool = true) {
//clearInterval(setInterval("scrollleft()", 500))
clearInterval(run);
run=setInterval("scrollright()", 500);
}
else {
//clearInterval(setInterval("scrollright()", 500))
clearInterval(run);
run=setInterval("scrollleft()", 500);
}
}
run=setInterval("scrollleft()",500);
</script>
</head>
<body>
<center>
<input type="button" value="向左转" onclick="judge()"/>
<input type="button" value="向右转" onclick="judge()"/>
</center>
</body>
</html>
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