How to learn JavaScript language? What are the important and difficult points in learning?-JS Tutorial-php.cn

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How to learn JavaScript language? What are the important and difficult points in learning?

巴扎黑

Jul 31, 2017 pm 01:59 PM

javascriptjs

JavaScript is a relatively complex scripting language. It may take a lot of effort to learn it, otherwise it will be difficult to learn the essence! Let’s take a look at what you need to learn when learning the JavaScript language.

1.Operator

var box1=100;
++box1;//相当于box=box+1
document.write("box1="+box1+"<br/>");//输出box1=101
var box2=100;
--box2;//相当于box=box2-1
document.write("box2="+box2);//输出box2=99

Recommend everyone to study the topicjavascript operator, which has a detailed explanation of operators

2.Expression

<html>
<head>
 <meta charset="utf-8">
 <title>php中文网(php.cn)</title>
</head>
<body>
<script>
 cars=["小明","小龙","小奇","小涛"];
 for (var i=0,l=cars.length; i<l; i++){
 document.write(cars[i] + "<br>");
 }
</script>
</body>
</html>

http://www.php.cn/code/3595.html

3. Statements

Javascript statements include: assignment statement, switch Select statement, while loop statement, for loop statement, for each loop statement, do while loop statement, break loop interruption statement, continue loop interruption statement, with statement, try...catch statement, if statement (if..else, if ...else if ...), let statement.

<html>
<head>
 <meta charset="utf-8">
 <title>php中文网(php.cn)</title>
</head>
<body>
<p>点击下面的按钮来显示今天是周几：</p>
<button onclick="myFunction()">点击这里</button>
<p id="demo"></p>
<script>
 function myFunction(){
 var x;
 var d=new Date().getDay();
 switch (d){
 case 0:x="今天是星期日";
 break;
 case 1:x="今天是星期一";
 break;
 case 2:x="今天是星期二";
 break;
 case 3:x="今天是星期三";
 break;
 case 4:x="今天是星期四";
 break;
 case 5:x="今天是星期五";
 break;
 case 6:x="今天是星期六";
 break;
 }
 document.getElementById("demo").innerHTML=x;
 }
</script>
</body>
</html>

http://www.php.cn/code/3601.html

4. Function

<html>
<head>
 <meta charset="utf-8">
 <title>php中文网(php.cn)</title>
</head>
<body>
<p>点击这个按钮，来调用带参数的函数。</p>
<button onclick="myFunction(&#39;哈利波特&#39;,&#39;Wizard&#39;)">点击这里</button>
<script>
 function myFunction(name,job){
 alert("Welcome " + name + ", the " + job);
 }
</script>
</body>
</html>

http:/ /www.php.cn/code/3580.html

5.Object

<html>
<head>
 <meta charset="utf-8">
 <title>php中文网（php.cn)</title>
</head>
<body>
<p>创建 JavaScript 对象。</p>
<p id="demo"></p>
<script>
 var person = {firstName:"John", lastName:"Doe", age:50, eyeColor:"blue"};
 document.getElementById("demo").innerHTML =
 person.firstName + " 现在 " + person.age + " 岁.";
</script>
</body>
</html>

http://www.php.cn/code/3575.html

6.Event

<html>
<head> 
<meta charset="utf-8"> 
<title>php中文网(php.cn)</title> 
</head>
<body>
<button onclick="getElementById(&#39;demo&#39;).innerHTML=Date()">现在的时间是?</button>
<p id="demo"></p>
</body>
</html>

http://www.php.cn/code/3594.html

7.Variable

<html>
<head>
 <meta charset="utf-8">
 <title>PHP中文网(php.cn)</title>
</head>
<body>
<p>点击这里来创建变量，并显示结果。</p>
<button onclick="myFunction()">点击这里</button>
<p id="demo"></p>
<script>
 function myFunction(){
 var carname="Volvo";
 document.getElementById("demo").innerHTML=carname;
 }
</script>
</body>
</html>

http://www.php.cn/code/3553.html

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