Basics
-
General:
- It's case sensitive
- End each statement with ;
- Very forgiving if you forget to close the statement with ;
- Not sensitive to white spaces (except in strings "" or line breaks.
- /* comments */ or // comments and the rest
- If you need it to create page, put in <head> otherwise, put it before </body>
- var abc, _xxx, $yyy; var year=2020; // JS a weakly typed language
- if ( condition ) { statements }
Keywords
- alert
- console.log
- true, false
- var
Find ...
- Aptana Studio
- Firebug
- JavaScript Checker
- Node.js
var a = document.getElementById ("mainTitle");
var b = document.getElementsByTagName ("li");
var b = document.getElementsByClassName ("description");
document.getElementById ("mainTitle").className = "highlight";
// JQuery Methods and Alias
jQuery(".discription").addClass("highlight");
$("myclass").addClass("highlight");
$("li").addclass("hightlight");
$("p:contains('packages')").hide(4000);
$("p").fadeOut(4000);
jQuery("#maintitle").removeClass("highlight");
jQuery("li:last").toggleClass("highlight");
$("#pageID").click (function() {
$("#pageID").text ("You clicked text!");
});
$("h2").click (function() {
$(this).text ("You clicked here!");
});
$("p").click (function() {
$(this).fadeOut (3000);
});
// Page load events - same as window.onload()
// But don't have to worry about calling it multiple times
$(document).ready(function () {
$("#pageID").text ("DOM fully loaded.");
});
$(document).ready(function () {
$("h1").css ("color", "red");
});
Example
<script>
console.log ("Download Git, Firebug and enable Console!")
var myvar = 1000;
newvar = 555; // skip "var" is okay but it is not a good practice.
var lineone = "this is line one.";
var just_the_num = lineone.slice(8);
console.log(just_the_num);
console.log(`Now we only have this part: ${just_the_num}`);
</script>
Only in Node.js:
// var path = require("path");
// console.log(__filename); // full pathname and file name
// console.log(__dirname); // full pathname to current directory
// alert(` remove the path: ${path.basename(__filename)}`);
// just the file name
Or put the code in another file "greeting.js", and
<script src="greeting.js" type="text/javascript">
// alert (greeting.firstline); // won't work
</script>
Useful Links:
Books:
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