函数定义与执行
<script type="text/javascript">
// 函数定义
function aa(){
alert('hello!');
}
// 函数执行
aa();
</script>
变量与函数预解析
<script type="text/javascript">
aa(); // 弹出 hello！
alert(bb); // 弹出 undefined
function aa(){
alert('hello!');
}
var bb = 123;
</script>
提取行间事件
<!--行间事件调用函数 -->
<script type="text/javascript">
function myalert(){
alert('ok!');
}
</script>
......
<input type="button" name="" value="弹出" onclick="myalert()">
<!-- 提取行间事件 -->
<script type="text/javascript">
window.onload = function(){
var oBtn = document.getElementById('btn1');
oBtn.onclick = myalert;
function myalert(){
alert('ok!');
}
}
</script>
......
<input type="button" name="" value="弹出" id="btn1">
匿名函数
<script type="text/javascript">
window.onload = function(){
var oBtn = document.getElementById('btn1');
/*
oBtn.onclick = myalert;
function myalert(){
alert('ok!');
}
*/
// 直接将匿名函数赋值给绑定的事件
oBtn.onclick = function (){
alert('ok!');
}
}
</script>
函数传参
<script type="text/javascript">
function myalert(a){
alert(a);
}
myalert(12345);
</script>
作业
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title>if练习1</title>
<script type="text/javascript">
var score = prompt("请输入小明的期末成绩(0-100):");
if(score > 100 || score < 0 || isNaN(score)){
alert("拉出去毙了~~~");
}else{
if(score == 100){
alert("宝马，拿去开~~~");
}else if(score >= 80){
alert("手机，拿去玩~~~");
}else if(score >= 60){
alert("参考书，拿去看~~~");
}else{
alert("棍子一根~~");
}
}
</script>
</head>
<body>
</body>
</html>
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title>if练习2</title>
<script type="text/javascript">
var height = prompt("请输入你的身高(CM):");
var money = prompt("请输入你的财富(万):");
var face = prompt("请输入你的颜值(PX):");
if(height > 180 && money > 1000 && face > 500){
alert("我一定要嫁给他~~");
}else if(height > 180 || money > 1000 || face > 500){
alert("嫁吧，比上不足，比下有余。");
}else{
alert("不嫁。");
}
</script>
</head>
<body>
</body>
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title>if练习3</title>
<script type="text/javascript">
var num1 = +prompt("请输入第一个数:");
var num2 = +prompt("请输入第二个数:");
var num3 = +prompt("请输入第三个数:");
alert(typeof num1);
//找到三个数中最小的数
if(num1 < num2 && num1 < num3){
//num1最小，比较num2和num3
if(num2 < num3){
//num1 num2 num3
alert(num1 +","+num2 + ","+num3);
}else{
//num1 num3 num2
alert(num1 +","+num3 + ","+num2);
}
}else if(num2 < num1 && num2 < num3){
//num2最小，比较num1和num3
if(num1 < num3){
//num2 num1 num3
alert(num2 +","+num1 + ","+num3);
}else{
//num2 num3 num1
alert(num2 +","+num3 + ","+num1);
}
}else{
//num3最小,比较num1和num2
if(num1 < num2){
// num3 num1 num2
alert(num3 +","+num1 + ","+num2);
}else{
//num3 num2 num1
alert(num3 +","+num2 + ","+num1);
}
}
</script>
</head>
<body>
</body>
</html>
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