JavaScript Summary: JavaScript learning Summary

JavaScript was invented by Netscape; syntax is very similar to Java; but note that Java and JavaScript have nothing to do with it.
There are many built-in objects in JavaScript that do not require user creation;
Tips for using HTML:
(1) If you want to output an empty table, you need <td> </td>
(2) in EditPlus to support the rapid browsing of the production of Web pages, shortcut keys are ctrl+b;
First, use JavaScript
If you want to introduce JavaScript into HTML, there are two ways:
(1) Internal introduction: JS code directly in the HTML writing;
The structure of the import is as follows:
<script language= "JavaScript" >
....
</script>
The general JS code is placed in the head tag;
(2) External introduction: JS code in the external writing after the import into the HTML;
<script language= "JavaScript" src= "1.js" >
....
</script>
Second, JavaScript grammar
1. Jump out of alert box
In JavaScript, the most used is alert, which causes the browser to pop up a prompt box;
Alert ("Hello world!!!"); You can pop a Hello world!!! the Prompt box;
<title></title>
<script language= "JavaScript" >
Alert ("Welcome!") ");
Alert ("Thank you!") ");
</script>
2. Page output content document.write ()
This statement is also very common and can output content directly to the page, such as:
document.write ("This statement is very similar to the OUT.PRINTLN () in the JSP;
<title></title>
<script language= "JavaScript" >
document.write ("</script>
3. Define variable var
This feature is very similar to Python, Java, there are a number of specific data types, but in JS, only need to give any type of value to Var;
For example:
(1) var num1 = 5; The type of NUM1 is an integer;
(2) var str1 = "Hello world!!!"; The type of str1 is a string;