Basic concepts of javascrpit:
1) Case sensitivity Just like JAVA, variables, functions, operators and everything else in JS are case sensitive. For example: the variables MyTag and MYTAG are two different variables .
2) Weak type change. So the so-called weakly typed variable refers to the fact that the variables in JS have no specific type, unlike C. Only use "var" to define a variable, and it can be initialized to any value, so that the type of data stored in the variable can be changed at will, which is not recommended;
Example: var age=25;
var myName="zhangsan";
3) The semicolon at the end of each line is optional;
Example:
var a=2
var b=3;
Note: If there is no semicolon, JS will default to the end of this line of code as the end of the statement;
4) Brackets are used for code blocks, and code blocks represent a series of codes that are executed in sequence. All are enclosed in JS curly braces "｛｝"
Example:
if(myName=="aa")
{
var age=67;
alert(age);
}
5) The way to comment is the same as C, C#, JAVA
//Single-line comments
/*
Multi-line comments
*/
For HTML pages , JS code is included between the <SCRIPT> and </SCRIPT> tags, and external JS documents can also be called through the SRC attribute in <SCRIPT>; <br> Example of a complete HTML page containing a JS document structure<br></p>
<div class="codetitle">
<span><a style="CURSOR: pointer" data="79587" class="copybut" id="copybut79587" onclick="doCopy('code79587')"><u>Copy code</u></a></span> The code is as follows:</div>
<div class="codebody" id="code79587"> <br><html> <br><head> <br> <title>The complete HTML page contains JS document structure</title> <br><script language="javascript"> <br>var myName="zhangsan"; <br>document.write(myName); <br></script>
