一：循环
for for in<!DOCTYPE html><html><head><meta charset="utf-8" /><meta http-equiv="X-UA-Compatible" content="IE=edge"><title>循环</title><meta name="viewport" content="width=device-width, initial-scale=1"><link rel="stylesheet" type="text/css" media="screen" href="main.css" /><script src="main.js"></script><script>var i = [1,2,3,4,5,6];for(j in i) {document.write(i[j]+"<br/>");}</script></head><body></body></html>
while do while break continue 函数调用 方法一：在script脚本中直接调用 方法二：在html中调用 带参数函数 带返回值函数
<!DOCTYPE html><html><head><meta charset="utf-8" /><meta http-equiv="X-UA-Compatible" content="IE=edge"><title>函数调用</title><meta name="viewport" content="width=device-width, initial-scale=1"><link rel="stylesheet" type="text/css" media="screen" href="main.css" /><script src="main.js"></script><script>//方法一 : 直接在script中调用function Demo1(a1,a2){alert(a1+a2);}Demo1(10,10); //直接调用function Demo2(){var a1 = 10;var a2 = 10;alert(a1+a2);}</script></head><body><!--在html中调用使用--><button onclick="Demo2()">按钮</button></body></html>
局部变量 全局变量
<!DOCTYPE html><html><head><meta charset="utf-8" /><meta http-equiv="X-UA-Compatible" content="IE=edge"><title>全局变量</title><meta name="viewport" content="width=device-width, initial-scale=1"><link rel="stylesheet" type="text/css" media="screen" href="main.css" /><script src="main.js"></script><script>var b = 30; //全局变量function Demo() {var a = 20; //局部变量 x = 10;//全局变量 }Demo();alert(x);//alert(a); //局部变量未执行 alert(b);</script></head><body></body></html>
异常捕获
<!DOCTYPE html><html><head><meta charset="utf-8" /><meta http-equiv="X-UA-Compatible" content="IE=edge"><title>异常捕获</title><meta name="viewport" content="width=device-width, initial-scale=1"><link rel="stylesheet" type="text/css" media="screen" href="main.css" /><script src="main.js"></script><script>function Demo(){try{alert(str); //发生异常的代码 }catch(err) {alert(err); //错误信息处理 }}//通过 throw 语句创建一个自定义错误function Demo1() {try {var t = document.getElementById("txt").value;if(t == "") {throw "请输入";}}catch(err) {alert(err);}} //Demo();</script></head><body><!--创建一个form表单 若输入框中输入的值为空，通过按钮触发警告--><form><input id="txt" type="text"/><br/><input id="btn" type="button" onclick="Demo1()" value="button"/></form></body></html>
事件
<!DOCTYPE html><html><head><meta charset="utf-8" /><meta http-equiv="X-UA-Compatible" content="IE=edge"><title>事件</title><meta name="viewport" content="width=device-width, initial-scale=1"><link rel="stylesheet" type="text/css" media="screen" href="main.css" /><script src="main.js"></script><script>//鼠标点击事件function click(){alert("onclick");}//鼠标经过和移出事件 鼠标经过div区域显示hello，移出后显示worldfunction onOver(ooj){ooj.innerHTML = "hello";}function onOut(ooj) {ooj.innerHTML = "world";}//文本框选中事件function selectText(obj) {obj.style.background = "red";}</script></head><body><button onclick="click()">单击点击事件</button><br/><!--鼠标经过事件 鼠标移出事件--><div style="width: 100px;height: 100px;background-color: lemonchiffon" onmouseover="onOver(this)" onmouseout="onOut(this)"></div><br/><!--文本内容改变事件--><form><input type="text" onchange="alert('文本输入框中的内容改变')"/></form><!--文本框选中事件 文本框的内容被选中后文本框显示为红色--><form><input type="text" onselect="selectText(this)"/></form><button onfocus="">光标聚集事件</button><button onblur="">移开光标事件</button><button onload="">网页加载事件</button><button onunload="">关闭网页事件</button></body></html>
