利用函数来修改HTML内容
<!DOCTYPE html>
<html>
<head>
<meta charset = "utf-8">
<title></title>
<script>
function dianwo(){
var div = document.getElementById("div1");
div.innerHTML = "<font color = 'red'>内容被替换掉了</font>";
div.innerText = "<font color = 'red'>内容被替换掉了</font>";
}
</script>
</head>
<body>
<input type = "button" value = "点我，弹框" onclick = "dianwo()">
<div id = "div1">
这里的内容一定要被替换掉
</div>
</body>
</html>注意下面的checkForm的返回值
<!DOCTYPE html>
<html>
<head>
<meta charset = "utf-8">
<title></title>
<script>
function checkForm(){
var input1 = document.getElementById("username");
var uValue = input1.value;
if(uValue.length >= 6){
return true;
}else{
alert("用户名太短");
}
return false;
}
</script>
</head>
<body>
<form action = "../01网站首页的优化/网站首页.html" onsubmit = "return checkForm()">
用户名：<input type = "text" id = "username"/><br />
<input type = "submit" value = "提交" />
</form>
</body>
</html>定时器案例
setInterval clearInterval
setTimeout clearTimeout
<!DOCTYPE html>
<html>
<head>
<meta charset = "utf-8">
<title></title>
<script>
function test(){
console.log("setInterval 调用了");
}
var timerID;
function startDinshiqi(){
timerID = setInterval("test()",2000);
}
function stopDinshiqi(){
clearInterval(timerID);
}
</script>
</head>
<body>
<input type = "button" value = "开启定时器" onclick = "startDishiqi()" /><br />
<input type = "button" value = "关闭定时器" onclick = "stopDishiqi()" /><br />
</body>
</html>