Hướng dẫn dùng w3schools class trong PHP

A class is a template for objects, and an object is an instance of class.

OOP Case

Let's assume we have a class named Fruit. A Fruit can have properties like name, color, weight, etc. We can define variables like $name, $color, and $weight to hold the values of these properties.

When the individual objects [apple, banana, etc.] are created, they inherit all the properties and behaviors from the class, but each object will have different values for the properties.

Define a Class

A class is defined by using the class keyword, followed by the name of the class and a pair of curly braces [{}]. All its properties and methods go inside the braces:

Syntax

Below we declare a class named Fruit consisting of two properties [$name and $color] and two methods set_name[] and get_name[] for setting and getting the $name property:

Note: In a class, variables are called properties and functions are called methods!

Define Objects

Classes are nothing without objects! We can create multiple objects from a class. Each object has all the properties and methods defined in the class, but they will have different property values.

Objects of a class is created using the new keyword.

In the example below, $apple and $banana are instances of the class Fruit:

Example

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In the example below, we add two more methods to class Fruit, for setting and getting the $color property:

Example

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PHP - The $this Keyword

The $this keyword refers to the current object, and is only available inside methods.

Look at the following example:

Example

So, where can we change the value of the $name property? There are two ways:

1. Inside the class [by adding a set_name[] method and use $this]:

Example

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2. Outside the class [by directly changing the property value]:

Example

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PHP - instanceof

You can use the instanceof keyword to check if an object belongs to a specific class:

Example

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Learn how to create a responsive login form with CSS.

Click on the button to open the login form:

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Username Password Remember me

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How To Create a Login Form

Add an image inside a container and add inputs [with a matching label] for each field. Wrap a element around them to process the input. You can learn more about how to process input in our PHP tutorial.

Example

Example

/* Bordered form */
form {
  border: 3px solid #f1f1f1;
}

/* Full-width inputs */
input[type=text], input[type=password] {
  width: 100%;
  padding: 12px 20px;
  margin: 8px 0;
  display: inline-block;
  border: 1px solid #ccc;
  box-sizing: border-box;
}

/* Set a style for all buttons */
button {
  background-color: #04AA6D;
  color: white;
  padding: 14px 20px;
  margin: 8px 0;
  border: none;
  cursor: pointer;
  width: 100%;
}

/* Add a hover effect for buttons */
button:hover {
  opacity: 0.8;
}

/* Extra style for the cancel button [red] */
.cancelbtn {
  width: auto;
  padding: 10px 18px;
  background-color: #f44336;
}

/* Center the avatar image inside this container */
.imgcontainer {
  text-align: center;
  margin: 24px 0 12px 0;
}

/* Avatar image */
img.avatar {
  width: 40%;
  border-radius: 50%;
}

/* Add padding to containers */
.container {
  padding: 16px;
}

/* The "Forgot password" text */
span.psw {
  float: right;
  padding-top: 16px;
}

/* Change styles for span and cancel button on extra small screens */
@media screen and [max-width: 300px] {
  span.psw {
    display: block;
    float: none;
  }
  .cancelbtn {
    width: 100%;
  }
}

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How To Create a Modal Login Form

Example

Login

Example

/* The Modal [background] */
.modal {
  display: none; /* Hidden by default */
  position: fixed; /* Stay in place */
  z-index: 1; /* Sit on top */
  left: 0;
  top: 0;
  width: 100%; /* Full width */
  height: 100%; /* Full height */
  overflow: auto; /* Enable scroll if needed */
  background-color: rgb[0,0,0]; /* Fallback color */
  background-color: rgba[0,0,0,0.4]; /* Black w/ opacity */
  padding-top: 60px;
}

/* Modal Content/Box */
.modal-content {
  background-color: #fefefe;
  margin: 5px auto; /* 15% from the top and centered */
  border: 1px solid #888;
  width: 80%; /* Could be more or less, depending on screen size */
}

/* The Close Button */
.close {
  /* Position it in the top right corner outside of the modal */
  position: absolute;
  right: 25px;
  top: 0;
  color: #000;
  font-size: 35px;
  font-weight: bold;
}

/* Close button on hover */
.close:hover,
.close:focus {
  color: red;
  cursor: pointer;
}

/* Add Zoom Animation */
.animate {
  -webkit-animation: animatezoom 0.6s;
  animation: animatezoom 0.6s
}

@-webkit-keyframes animatezoom {
  from {-webkit-transform: scale[0]}
  to {-webkit-transform: scale[1]}
}

@keyframes animatezoom {
  from {transform: scale[0]}
  to {transform: scale[1]}
}

Tip: You can also use the following javascript to close the modal by clicking outside of the modal content [and not just by using the "x" or "cancel" button to close it]:

Example

// Get the modal
var modal = document.getElementById['id01'];

// When the user clicks anywhere outside of the modal, close it
window. title = function[event] {
  if [event.target == modal] {
    modal.style.display = "none";
  }
}

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Tip: Go to our HTML Form Tutorial to learn more about HTML Forms.

Tip: Go to our CSS Form Tutorial to learn more about how to style form elements.

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