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[英]Javascript Uncaught ReferenceError: parameter is not defined
[英]Uncaught ReferenceError: “changing” is not defined (JavaScript)
我试图做一个函数,当一个
单击“ Try it”按钮,并在函数内部运行循环,在该函数中使用循环更改单词
我是JavaScript新手,但是对编程却很老。
与C或C ++相比有点令人困惑
<!DOCTYPE html>
<html>
<head>
<style>
#demo {
font-size: 600%;
color: red;
}
</style>
<script>
function changing() {
var my = undefined;
for (count = 1; count < 3; count++) {
if (count == 1) {
my = LIFE;
document.getElementById('demo').innerHTML = my;
} else if (count == 2) {
my = STYLE;
document.getElementById('demo').innerHTML = my;
} else if (count == 3) {
{
break;
}
}
}
</script>
</head>
<body>
<h1>My First Web Page</h1>
<p>My first paragraph.</p>
<div id="demo">AWESOME</div>
<button type="button" onclick="changing()">Try it</button>
</body>
</html>
错误部分:
else if (count == 3) {
{
您打开了2个花括号
还利用"LIFE"
,而不是LIFE
和"STYLE"~ instead of
STYLE`
function changing() { var my = undefined; for (count = 1; count < 3; count++) { if (count == 1) { my = "LIFE"; document.getElementById('demo').innerHTML = my; } else if (count == 2) { my = "STYLE"; document.getElementById('demo').innerHTML = my; } else if (count == 3) { break; } } }
<!DOCTYPE html> <html> <head> <style> #demo { font-size: 600%; color: red; } </style> </head> <body> <h1>My First Web Page</h1> <p>My first paragraph.</p> <div id="demo">AWESOME</div> <button type="button" onclick="changing()">Try it</button> </body> </html>
在使用strings
时,请记住有关引号的信息。 否则,它将被视为variable
。 而且由于尚未声明-函数将引发错误。
function changing() { var my; for (count = 1; count < 3; count++) { if (count == 1) { my = 'LIFE'; document.getElementById('demo').innerHTML = my; } else if (count == 2) { my = 'STYLE'; document.getElementById('demo').innerHTML = my; } else if (count == 3) { break; } } }
#demo { font-size: 600%; color: red; }
<h1>My First Web Page</h1> <p>My first paragraph.</p> <div id="demo">AWESOME</div> <button type="button" onclick="changing()">Try it</button>
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