JavaScript and CSS
for PL/SQL Developers

Jorge Rimblas

Jorge Rimblas

Senior APEX Consultant

@rimblas

rimblas.com/blog

  • Oracle DB since 1995
  • APEX since it was HTMLDB in 2004
  • Always involved in web technologies
  • jrimblas in OTN Forums
  • Contributor to
    "Expert Oracle Application Express, 2nd Edition"
    with "Themes & Templates" chapter

Age: 14 years!
Staff: 80+ employees
60 consultants/developers
APEX Solutions: 12 Years!
Largest APEX practice in North America
Oracle Center of Excellence

 

 

Are you comfortable with
Oracle PL/SQL?

How about with JavaScript?

and CSS?

Everything is a BOX

CSS Specificity

In CSS

biggest issue

JavaScript

  • runs the web
  • interpreted
  • all browser support

Just heard this one from someone at @AmsterdamPHP: "Java is to Javascript like what ham is to hamster" 😂👍

— Claudio Dekker (@ClaudioDekker) February 16, 2017

Java is to JavaScript 

as

Ham is to Hamster

Operator JavaScript PL/SQL
assignment = :=
equality == = 
if (i = 1) {
...
}
if (1) {
...


if (i = 1) then
...

PL/SQL

JS

=== !==

JavaScript equality operators

the evil twins

==  !=
'' == '0'           // false
0 == ''             // true
0 == '0'            // true

false == 'false'    // false
false == '0'        // true

false == undefined  // false
false == null       // false
null == undefined   // true

' \t\r\n ' == 0     // true

* stackoverflow.com/questions/359494/which-equals-operator-vs-should-be-used-in-javascript-comparisons

Operator JavaScript PL/SQL
assignment = :=
strict equality === =
strict inequality !== !=
<>
Operator JavaScript PL/SQL
or || or
concatenation + ||
Addition + + 
0 + 0       // 0
"0" + 0     // "00"
"0" + "0"   // "00"
0 + "0"     // "00"
Operator JavaScript PL/SQL
++ v++
++v		 v := v+1;
 
-- v--
--v		 v := v-1; 
var i = 5;

++i + 4     // = 10, i = 6
i++ + 4     // =  9, i = 6

function foo(n) {
  i = n;
} 
function foo(n number) 
  return number
is
  i number;
begin
  i := n;
end foo;

JS

PL/SQL

function foo(n number) 
  return number
is
  i number;
begin
  i := n;
  return i;
end foo;
  • May return nothing
  • No "procedures"
ORA-06503: PL/SQL: Function returned without value
function foo(x, y) {
  return x * y;
} 
foo(1,2);
// 2

Definition

JS has flexible parameters

foo(1,2,7,8);
// 2
foo(5);
// NaN
function foo(x, y) {
  return x * y;
}

Definition

Functions and Variable Functions

var foo = function (x, y) {
  return x * y;
}

also a function

typeof foo;
// function
eval

It's always a no-no. Big security risk

$

jQuery

jQuery is a fast, small, and feature-rich JavaScript library.

It makes things like HTML document traversal and manipulation, event handling, animation, and Ajax much simpler with an

easy-to-use API that works across a multitude of browsers.

 

With a combination of versatility and extensibility, jQuery has changed the way that millions of people write JavaScript.

 

Source: jquery.com

$ === apex.jQuery


$("div");

apex.jQuery("div");


CSS

Everything is a BOX

CSS Specificity

In CSS

biggest issue

Box Model

Inspector

 

Content

 

Padding

Border

Margin

<div>Content</div>
div {
    width: 320px;  height: 50px;
    padding: 10px;


}
div {
    width: 320px;  height: 50px;



}
div {
    width: 320px;  height: 50px;
    padding: 10px;
    border: 5px solid gray;

}
div {
    width: 320px;  height: 50px;
    padding: 10px;
    border: 5px solid gray;
    margin: 7px; 
}
div {
    width: 320px;
    padding: 10px;
    border: 5px solid gray;
    margin: 0; 
}
320px (width)
+ 20px (left + right padding)
+ 10px (left + right border)
+ 0px (left + right margin)
= 350px

Total width?

Anatomy

of a CSS Rule

div {
    width: 320px;
    padding: 10px;
    border: 5px solid gray;
    margin: 0; 
}

selector

property

value

property

value

jQuery selector

div {
    padding: 10px;
}
div {
    padding: 10px 10px 10px 10px;
}

top

bottom

right

left

shorthand

div {
    padding: 5px 10px;
}
div {
    padding: 5px 10px 5px 10px;
}

top

bottom

right

left

top

right

bottom

left

div {
    padding: 5px 10px 5px 10px;
}

top

right

bottom

left

div {
    padding-top: 5px;
    padding-right: 10px;
    padding-bottom: 5px;
    padding-left: 10px;
}

Selectors

select *
from emp
where deptno = 20

SQL "Selector"

What are we looking for?

select element
from {Page HTML}

SQL

* {
 ...
}

CSS

Get Everything

select element
from {Page HTML}
where id = 'PK'

SQL

#PK {
 ...
}

CSS

Get By #ID

<div id="emps" class="t-Region">
  ...
</div>

HTML

#emps {
 color: red;
}

CSS

Get By #ID

select element
from {Page HTML}
where job = 'SALES'

SQL

.sales {
 ...
}

CSS

Get By .class

<div id="emps" class="t-Region">
  ...
</div>

HTML

.t-Region {
 color: red;
}

CSS

Get By .class

<td class="t-Report-cell" headers="EMPNO">
  ...
</td>

HTML

td[headers="EMPNO"] {
 color: red;
}

CSS

Get By attribute []

~=
|=
^=
$=
select element
from {Page HTML}
where deptno = 20

SQL

div {
 ...
}

CSS

Get By element

<div id="emps" class="t-Region">
  ...
</div>

HTML

div {
 color: red;
}

CSS

Get By element

<div id="emps" class="t-Region t-Region--removeHeader">
  ...
</div>
.t-Region {
 background-color: white;
}
#emps {
 background-color: gray;
}
div {
 background-color: blue;
}

<div id="emps" class="t-Region t-Region--removeHeader">
  ...
</div>
.t-Region {
 background-color: white;
 border: 1px solid black;
}
.t-Region {
 background-color: gray;
}

<div id="emps" class="t-Region t-Region--accent5" 
     style="background-color: green;">
  ...
</div>
.t-Region {
 background-color: white;
}
.t-Region.t-Region--accent5 {
 background-color: gray;
}
#emps {
 background-color: blue;
}

.t-Region {...}

$(".t-Region");
.t-Region.t-Region--accent5 {...}

$(".t-Region.t-Region--accent5");

CSS

jQuery

CSS

jQuery

#emps {...}

$("#emps");

CSS

jQuery

$(".t-Region").hide();
$(".t-Region").remove();
$(".t-LinksList-item").toggleClass("is-current");
$("#emp").find("li").removeClass("is-current");

jquery.com

CSS Specificity

Style Attribute Most Specific
ID
Class, Attribute
Elements Least Specific

* https://css-tricks.com/specifics-on-css-specificity/

<div id="emps" class="t-Region t-Region--accent5" 
     style="background-color: green;">
  ...
</div>
.t-Region {
 background-color: white!important;
}
.t-Region.t-Region--accent5 {
 background-color: gray;
}
#emps {
 background-color: blue;
}

!Important

The Automatic Win

Placing
CSS
in APEX

Page CSS: file or inline

Useful for

  • Page specific CSS
    • Items
    • Buttons
    • CSS Overrides
    • Report columns

Theme Roller: Custom CSS

Pros

  • Available to ALL pages
  • Minimized
  • Fast & Easy to update

Cons

  • Lost when you switch styles
    • Good idea to maintain on a file

Global User Interface File

Global User Interface File

Best approach!

 

 

Q&A

JavaScript and CSS
for PL/SQL Developers

Jorge Rimblas

rimblas.com/blog/presentations

Twitter: @rimblas

JavaScript and CSS for PL/SQL Developers

By Jorge Rimblas

JavaScript and CSS for PL/SQL Developers

If you have been working with the Oracle Database for a while, but still feel lost when working with JavaScript and CSS in your APEX applications, then this session is for you. Working with HTML, JavaScript, and CSS doesn't have to be hard. Learn about CSS selectors, what is the DOM and working with it, JavaScript functions, and even some jQuery. This session will provide you some tools to work better with web technologies.

  • 5,288

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