1.面向?qū)ο?/h2>
<script>
var message="hello world!";
var x=message.length;
var y=message.toUpperCase();
document.write(x);
document.write(y);
</script>
字符串長度以及轉(zhuǎn)換為大寫.png
2.函數(shù)調(diào)用
<body>
<button onclick="myfunction()">點擊這里</button>
<button onclick="clon('ghl','lxz')">點擊有驚喜</button>
<button onclick="clon('lqs','zh')">點擊有驚喜</button>
<script>
function myfunction(){
alert("Hello World!");
}
function clon(name,home){
alert("我是" + name + "和" + home + "的爸爸放妈。");
}
</script>
</body>
第一個按鈕.png
第二個按鈕.png
第三個按鈕.png
3.帶有返回值的函數(shù)
<p id="demo"></p>
<script>
function myfunction(x,y){
return x/y;
}
document.getElementById("demo").innerHTML=myfunction(90,6)
</script>
帶有返回值的函數(shù).png
4.算術(shù)
<script>
var x = 5;
var y = 10;
var z = 15;
txt1 = "What a very ";
txt2 = "nice day";
txt = txt1 + "" + txt2;
document.write(x);
document.write(x += y);
document.write("<br />");
document.write(x -= z);
document.write("<br />");
document.write(x + "20");
document.write("<br />");
document.write(x % y);
document.write(txt);
</script>
算術(shù).png
5.比較
5.1 比較運算符
比較運算符.png
5.2 邏輯運算符
邏輯運算符.png
5.3 條件運算符
條件運算符.png
6.if..else
<p>設(shè)原x為“時間過得好快”瘤礁，如果當(dāng)前時間小于15時迈喉，則輸出“時間過得好慢”，反之顯示原x的值隶垮。</p>
<button onclick="ps()">點擊這里</button>
<p id="demo"></p>
<br>
<br>
<br>
<br>
<br>
<button onclick="ps01()">點擊這里</button>
<p id="one"></p>
<script>
function ps(){
var x="時間過得好快"
var time = new Date().getDate();
if(time<15)
{
x="時間過得好慢";
}
document.getElementById("demo").innerHTML=x;
}
//或者用if..else
function ps01(){
var time=new Date().getDate();
if(time<15)
{
y="時間過得好慢啊";
}
else
{
y="時間過得好快啊";
}
document.getElementById("one").innerHTML=y;
}
</script>
if..else.png
7.switch(轉(zhuǎn)換) 匹配執(zhí)行代碼塊
<h1>switch 語句用于基于不同的條件來執(zhí)行不同的動作</h1>
<h3>工作原理：首先設(shè)置表達式 n（通常是一個變量）。隨后表達式的值會與結(jié)構(gòu)中的每個 case 的值做比較羡藐。如果存在匹配怀薛，則與該 case 關(guān)聯(lián)的代碼塊會被執(zhí)行。請使用 break 來阻止代碼自動地向下一個 case 運行</h3>
<button onclick="myfunction()">點擊顯示星期幾</button>
<p id="demo"></p>
<h3>default 關(guān)鍵詞來規(guī)定匹配不存在時做的事情</h3>
<p id="one"></p>
<script>
function myfunction() {
var x;
var d = new Date().getDay();
var e = new Date().getDay();
switch (d) {
case 0:
x = "Today it's Sunday";
break;
case 1:
x = "Today it's Monday";
break;
case 2:
x = "Today it's Tuesday";
break;
case 3:
x = "Today it's Wednesday";
break;
case 4:
x = "Today it's Thursday";
break;
case 5:
x = "Today it's Friday";
break;
case 6:
x = "Today it's Saturday";
break;
}
switch (e) {
case 2:
y = "Today it's Tuesday";
break;
case 3:
y = "Today it's Wednesday";
break;
default:
y = "今天不用打盧克";
}
document.getElementById("demo").innerHTML = x;
document.getElementById("one").innerHTML = y;
}
</script>
switch.png
8.for循環(huán)
8.1
<script>
names = ["平帥", "張路", "胡凱", "梁昊天", "劉奎元"];
for ( var i = 0; i < names.length; i++) {
document.write(names[i] + "<br>");
}
</script>
01.png
8.2
<button onclick="myfunction()">點擊這里</button>
<p id="demo"></p>
<script>
var x="";
function myfunction() {
for (var i = 0; i < 7; i++) {
x =x + "這個數(shù)字是" + i + "<br>";
}
document.getElementById("demo").innerHTML = x;
}
</script>
02.png
8.3 for/in 循環(huán)
<button onclick="myfunction()">點擊這里</button>
<p id="demo"></p>
<script>
function myfunction() {
var x;
var txt = "";
var person = { franme: "平", lname: "帥", age: 20 };
for (x in person) {
txt = txt + person[x];
}
document.getElementById("demo").innerHTML = txt;
}
</script>
03.png
