菜鸟学习javascript实例教程
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菜鸟学习javascript实例教程
用JS显示文字的例子：
<html>
<body>
<script type="text/javascript"> document.write("Hello World!")
</script>
</body>
</html>
用HTML标签来格式化文本的例子：
<html>
<body>
<script type="text/javascript"> document.write("<h1>Hello World!</h1>") </script>
</body>
</html>
书写JS位置的例子：
打开页面弹出窗口的例子
<html>
<head>
<script type="text/javascript">
function message()
{
alert("网页教学网欢迎你的光临")
}
</script>
</head>
<body onload="message()">
</body>
</html>
在BODY区内输出显示文本的例子：
<html>
<head>
</head>
<body>
<script type="text/javascript">
document.write("欢迎光临网页教学网")
</script>
</body>
</html>
调用其它的一个JS文件的例子：
<html>
<head>
</head>
<body>
<script src="xxx.js">
</script>
<p>
The actual script is in an external script file called "xxx.js". </p>
</body>
</html>
变量的使用
变量使用的例子：
<html>
<body>
<script type="text/javascript">
var name = "Hege"
document.write(name)
document.write("<h1>"+name+"</h1>")
</script>
<p>This example declares a variable, assigns a value to it, and then displays the variable.</p>
<p>Then the variable is displayed one more time, only this time as a heading.</p>
</body>
</html>
函数的例子
函数使用的一个例子：
<html>
<head>
<script type="text/javascript">
function myfunction()
{
alert("HELLO")
}
</script>
</head>
<body>
<form>
<input type="button"
onclick="myfunction()"
value="Call function">
</form>
<p>By pressing the button, a function will be called. The function will alert a message.</p>
</body>
</html>
带一个参数的函数的例子：
<html>
<head>
<script type="text/javascript">
function myfunction(txt)
{
alert(txt)
}
</script>
</head>
<body>
<form>
<input type="button"
onclick="myfunction('Hello')"
value="Call function">
</form>
<p>By pressing the button, a function with an argument will be called. The function will alert
this argument.</p>
</body>
</html>
不同的两个参数调用函数的例子：
<html>
<head>
<script type="text/javascript">
function myfunction(txt)
{
alert(txt)
}
</script>
</head>
<body>
<form>
<input type="button"
onclick="myfunction('Good Morning!')"
value="In the Morning">
<input type="button"
onclick="myfunction('Good Evening!')"
value="In the Evening">
</form>
When you click on one of the buttons, a function will be called. The function will alert
the argument that is passed to it.
</p>
</body>
</html>
利用函数返回值的例子：
<html>
<head>
<script type="text/javascript">
function myFunction()
{
return ("Hello, have a nice day!")
}
</script>
</head>
<body>
<script type="text/javascript">
document.write(myFunction())
</script>
<p>The script in the body section calls a function.</p>
<p>The function returns a text.</p>
</body>
</html>
带参数的函数返回值的例子：
<html>
<head>
<script type="text/javascript">
function total(numberA,numberB)
{
return numberA + numberB
</script>
</head>
<body>
<script type="text/javascript">
document.write(total(2,3))
</script>
<p>The script in the body section calls a function with two arguments, 2 and 3.</p> <p>The function returns the sum of these two arguments.</p>
</body>
</html>
条件语句的例子
简单条件语句的例子：
<html>
<body>
<script type="text/javascript">
var d = new Date()
var time = d.getHours()
if (time < 10)
{
document.write("<b>Good morning</b>")
}
</script>
<p>
This example demonstrates the If statement.
</p>
<p>
If the time on your browser is less than 10,
you will get a "Good morning" greeting.
</p>
</body>
</html>
if ... else 的条件语句的例子：
<html>
<body>
<script type="text/javascript">
var d = new Date()
var time = d.getHours()
if (time < 10)
{
document.write("<b>Good morning</b>")
}
else
{
document.write("<b>Good day</b>")
}
</script>
<p>
This example demonstrates the If...Else statement. </p>
<p>
If the time on your browser is less than 10,
you will get a "Good morning" greeting.
Otherwise you will get a "Good day" greeting.
</p>
</body>
</html>
用随机数产生连接的例子：
<html>
<body>
<script type="text/javascript">
var r=Math.random()
if (r>0.5)
document.write("<a href=''>Learn Web Development!</a>") }
else
{
document.write("<a href='http://www.refsnesdata.no'>Visit Refsnes Data!</a>") }
</script>
</body>
</html>
多条件的语句实现的例子：
<html>
<body>
<script type="text/javascript">
var d = new Date()
theDay=d.getDay()
switch (theDay)
{
case 5:
document.write("Finally Friday")
break
case 6:
document.write("Super Saturday")
break
case 0:
document.write("Sleepy Sunday")
break
default:
document.write("I'm really looking forward to this weekend!")
}
</script>
<p>This example demonstrates the switch statement.</p>
<p>You will receive a different greeting based on what day it is.</p>
<p>Note that Sunday=0, Monday=1, Tuesday=2, etc.</p>
</body>
</html>
循环的例子：
for循环的一个例子：
<html>
<body>
<script type="text/javascript">
for (i = 0; i <= 5; i++)
{
document.write("The number is " + i)
document.write("<br>")
}
</script>
<p>Explanation:</p>
<p>The for loop sets <b>i</b> equal to 0.</p>
<p>As long as <b>i</b> is less than , or equal to, 5, the loop will continue to run.</p>
<p><b>i</b> will increase by 1 each time the loop runs.</p>
</body>
</html>
复杂循环的一个例子：
<html>
<body>
<script type="text/javascript">
for (i = 1; i <= 6; i++)
{
document.write("<h" + i + ">This is header " + i)
document.write("</h" + i + ">")
}
</script>
</body>
</html>
按条件循环while的例子：
<html>
<body>
<script type="text/javascript">
i = 0
while (i <= 5)
{
document.write("The number is " + i)
document.write("<br>")
i++
}
</script>
<p>Explanation:</p>
<p><b>i</b> equal to 0.</p>
<p>While <b>i</b> is less than , or equal to, 5, the loop will continue to run.</p> <p><b>i</b> will increase by 1 each time the loop runs.</p>
</body>
</html>
do...while循环的例子：
<html>
<body>
<script type="text/javascript">
i = 0
do
{
document.write("The number is " + i)
document.write("<br>")
i++
}
while (i <= 5)
</script>
<p>Explanation:</p>
<p><b>i</b> equal to 0.</p>
<p>The loop will run</p>
<p><b>i</b> will increase by 1 each time the loop runs.</p>
<p>While <b>i</b> is less than , or equal to, 5, the loop will continue to run.</p>
</body>
</html>
字符串对象的例子：
检测字符串长度的例子：
<html>
<body>
<script type="text/javascript">
var str="W3Schools is great!"
document.write("<p>" + str + "</p>")
document.write(str.length)
</script>
</body>
</html>
检测子字符串位置的例子：
<html>
<body>
<script type="text/javascript">
var str="W3Schools is great!"
var pos=str.indexOf("School")
if (pos>=0)
{
document.write("School found at position: ")
document.write(pos + "<br />")
}
else
{
document.write("School not found!")
}
</script>
<p>This example tests if a string contains a specified word. If the word is found it returns the position of the first character of the word in the original string. Note: The first position in the string is 0!</p>
</body>
</html>。