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A rough understanding of an effort to get started
1. Introduction of external script in HTML: <script src= "Filename.js" ></script>
2. Note: Long comments with more than one line use the/* Comment content */, only a single line of comments with//comment content.
3. Create the format of the function:
Function name () {
The contents of the function
}
A variable created inside a function is a local variable that is valid only within the function, and the variable created outside of all functions is a global variable that can be used anywhere in the code.
4. getElementById () obtain and manipulate elements by ID;
Getelementbyvalue () acquiring and manipulating elements through value
5. Dot syntax: Object. Properties. Method
6. The keyword this points to the object, which can be used to pass values to the function using its context. The context in most cases refers to the object that encapsulates this function when the function is run.
9, if () ... else ... Statement
if (condition) {
Statement executed when the condition is true
}
else{
Statement executed when the condition is false
}
10. Switch (variable) {
Case value 1:
The statement that is executed when the value of the variable variable is 1
Break
Case Value 2:
The statement that is executed when the value of the variable variable is 1
Break
Case Value 3:
The statement that is executed when the value of the variable variable is 1
Break
.
.
.
Case Value N:
The statement that is executed when the value of the variable variable is 1
Break
Default: Statement executed when the value of the variable variable does not match any of the above values
}
Break: When the value of a variable is equal to the value following the case, leave the switch statement, or continue execution down.
11. Try Catch Throw
This part of the content in the following links have more detailed explanation http://www.w3school.com.cn/js/js_errors.asp
12. For loop
For example: for (var i=0;i< a value; i++) {
code block (as long as the counter variable i< a value, loop through this block of code)
}
13. Arrays
For example:
var baiyu=new Array ("Xiang", "Yu", "Yong", "Shang"); Declaring a string array
var number=new array (1,3,4,6,7,5,3,2);//declaring a numeric array
var bai=new array (66);//declares a new array containing 66 objects
To call an array in the form of an array name []
14, do not know how many times the code loop when using the Do/while loop
do{
Code Block 1
}
while (code block 2);
Loop executes code block 1 as long as the result of code block 2 is true.
15. Image Processing
Made a fun flip-up (though the general flip-out is not used)
Effect:
HTML code: <! DOCTYPE html>
<link href= "Bear.css" rel= "stylesheet" type= "Text/css" >
<script src= "Bear.js" ></script>
<body>
<a href= "lefteye.html" ></a>
<a href= "right.html" ></a>
</body>
CSS code:
body{
width:600px;
height:400px;
margin:0 Auto;
margin-top:120px;
}
img{
margin:0;
Float:left;
}
JavaScript code:
Window.onload=initeyes;
function Initeyes () {
document.getElementById ("left"). Onmouseover=leftopen;
document.getElementById ("left"). Onmouseout=leftclose;
document.getElementById ("right"). Onmouseover=rightopen;
document.getElementById ("right"). Onmouseout=rightclose;
}
function Leftopen () {
This.src= "Images/leftopen.gif";
}
function Leftclose () {
This.src= "Images/leftclose.gif";
}
function Rightopen () {
This.src= "Images/righttopen.gif"; }
function Rightclose () {
This.src= "Images/rightclose.gif"; }
A lot of the repetitive parts of this JavaScript code might be able to make the code more concise in a way like a template class in C + +. Looking forward to the next study.
PS: The picture used is made by the plate +ps.
JavaScript Basics Grooming (1)
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