Sunday, July 8, 2018

HTML Images


Images can improve the design and the appearance of a web page.

Example :


<img src="pic_trulli.jpg" alt="Italian Trulli">

Example :


<img src="img_girl.jpg" alt="Girl in a jacket">

Example :


<img src="img_chania.jpg" alt="Flowers in Chania">

HTML Images Syntax

In HTML, images are defined with the <img> tag.

The <img> tag is empty, it contains attributes only, and does not have a closing tag.

The src attribute specifies the URL (web address) of the image:

<img src="url">

The alt Attribute

The alt attribute provides an alternate text for an image, if the user for some

 reason cannot view it (because of slow connection, an error in the src attribute, or if

 the user uses a screen reader).

The value of the alt attribute should describe the image:

Example :


<img src="img_chania.jpg" alt="Flowers in Chania">

If a browser cannot find an image, it will display the value of the alt attribute:

Example :


<img src="wrongname.gif" alt="Flowers in Chania">

Note: The alt attribute is required. A web page will not validate correctly without it.

Image Size - Width and Height

You can use the style attribute to specify the width and height of an image.

Example :


<img src="img_girl.jpg" alt="Girl in a jacket"  style="width:500px;              height:600px;">


Alternatively, you can use the width and height attributes:

Example :


<img src="img_girl.jpg" alt="Girl in a jacket" width="500" height="600">


The width and height attributes always defines the width and height of the image in pixels.


Note: Always specify the width and height of an image. If width and height are not specified, the page might flicker while the image loads.

Width and Height, or Style?

The width, height, and style attributes are valid in HTML5.

However, we suggest using the style attribute. It prevents styles sheets from 

changing the size of images:

Example :


<!DOCTYPE html>
<html>
<head>
<style>
img { 
    width:100%; }</style>
</head>
<body>

<img src="html5.gif" alt="HTML5 Icon" width="128" height="128">
<img src="html5.gif" alt="HTML5 Icon" style="width:128px;height:128px;">

</body>
</html>


Images in Another Folder

If not specified, the browser expects to find the image in the same folder as the web page.

However, it is common to store images in a sub-folder. You must then include the 

folder name in the src attribute:


Example :

<img src="/images/html5.gif" alt="HTML5 Icon" style="width:128px;height:128px;">

Images on Another Server

Some web sites store their images on image servers.

Actually, you can access images from any web address in the world:

Example :


<img src="https://www.webmasterw.com/images/w3schools_green.jpg" alt="W3Schools.com">


Animated Images

HTML allows animated GIFs:

Example :


<img src="programming.gif" alt="Computer Man" style="width:48px;height:48px;">

Image as a Link

To use an image as a link, put the <img> tag inside the <a> tag:

Example :


<a href="default.asp">
  <img src="smiley.gif" alt="HTML tutorial" style="width:42px;height:42px;border:0;">
</a>

Note: border:0; is added to prevent IE9 (and earlier) from displaying a border around the image (when the image is a link).


Image Floating

Use the CSS float property to let the image float to the right or to the left of a text:


Example :


<p><img src="smiley.gif" alt="Smiley face" style="float:right;width:42px;height:42px;">
The image will float to the right of the text.</p>

<p><img src="smiley.gif" alt="Smiley face" style="float:left;width:42px;height:42px;">
The image will float to the left of the text.</p>

Image Maps

The <map> tag defines an image-map. An image-map is an image with clickable areas.
In the image below, click on the computer, the phone, or the cup of coffee:


Example :


<img src="workplace.jpg" alt="Workplace" usemap="#workmap">

<map name="workmap">
  <area shape="rect" coords="34,44,270,350" alt="Computer" href="computer.htm">
  <area shape="rect" coords="290,172,333,250" alt="Phone" href="phone.htm">
  <area shape="circle" coords="337,300,44" alt="Coffee" href="coffee.htm">
</map>


The name attribute of the <map> tag is associated with the <img>'s usemap 

attribute and creates a relationship between the image and the map.

The <map> element contains a number of <area> tags, that define the clickable

 areas in the image-map.

Background Image

To add a background image on an HTML element, use the CSS property background-image:


Example

To add a background image on a web page, specify the background-image property on the BODY element:


<body style="background-image:url('clouds.jpg')">

<h2>Background Image</h2>

</body>

Example

To add a background image on a paragraph, specify the background-image property on the P element:


<body>

<p style="background-image:url('clouds.jpg')">
...
</p>

</body>


The <picture> Element

HTML5 introduced the <picture> element to add more flexibility when specifying 

image resources.

The <picture> element contains a number of <source> elements, each referring to 

different image sources. This way the browser can choose the image that best fit the 

current view and/or device.

Each <source> element have attributes describing when their image is the most suitable.

The browser will use the first <source> element with matching attribute values, and

 ignore any following <source>elements.

Example

Show one picture if the browser window (viewport) is a minimum of 650 pixels, and 

another image if not, but larger than 465 pixels.

<picture>
  <source media="(min-width: 650px)" srcset="img_pink_flowers.jpg">
  <source media="(min-width: 465px)" srcset="img_white_flower.jpg">
  <img src="img_orange_flowers.jpg" alt="Flowers" style="width:auto;">
</picture>


Note: Always specify an <img> element as the last child element of the <picture> element. The <img>element is used by browsers that do not support the <picture> element, or if none of the <source> tags matched.


HTML Screen Readers

A screen reader is a software program that reads the HTML code, converts the text,

 and allows the user to "listen" to the content. Screen readers are useful for people

 who are blind, visually impaired, or learning disabled.


Chapter Summary

  • Use the HTML <img> element to define an image
  • Use the HTML src attribute to define the URL of the image
  • Use the HTML alt attribute to define an alternate text for an image, if it cannot be displayed
  • Use the HTML width and height attributes to define the size of the image
  • Use the CSS width and height properties to define the size of the image (alternatively)
  • Use the CSS float property to let the image float
  • Use the HTML <map> element to define an image-map
  • Use the HTML <area> element to define the clickable areas in the image-map
  • Use the HTML <img>'s element usemap attribute to point to an image-map
  • Use the HTML <picture> element to show different images for different devices
























Posted by at No comments:

HTML Links


Links are found in nearly all web pages. Links allow users to click their way from page to page.

HTML Links - Hyperlinks

HTML links are hyperlinks.

You can click on a link and jump to another document.

When you move the mouse over a link, the mouse arrow will turn into a little hand.
Note: A link does not have to be text. It can be an image or any other HTML element.

HTML Links - Syntax

In HTML, links are defined with the <a> tag:


<a href="url">link text</a>


Example :


<a href="https://www.webmasterw.com/html/">Visit our HTML tutorial</a>

The href attribute specifies the destination address 

(https://www.w3schools.com/html/) of the link.

The link text is the visible part (Visit our HTML tutorial).

Clicking on the link text will send you to the specified address.
Note: Without a forward slash at the end of subfolder addresses, you might generate two requests to the server. Many servers will automatically add a forward slash to the end of the address, and then create a new request.

Local Links

The example above used an absolute URL (a full web address).

A local link (link to the same web site) is specified with a relative URL (without 

http://www....).



Example :

<a href="html_images.asp">HTML Images</a>


HTML Link Colors

By default, a link will appear like this (in all browsers):
  • An unvisited link is underlined and blue
  • A visited link is underlined and purple
  • An active link is underlined and red
You can change the default colors, by using CSS:

Example :


<style>
a:link {
    color: green; 
    background-color: transparent; 
    text-decoration: none;}

a:visited {
    color: pink;
    background-color: transparent;
    text-decoration: none;}

a:hover {
    color: red;
    background-color: transparent;
    text-decoration: underline;}

a:active {
    color: yellow;
    background-color: transparent;
    text-decoration: underline;}
</style>




HTML Links - The target Attribute

The target attribute specifies where to open the linked document.

The target attribute can have one of the following values:
  • _blank - Opens the linked document in a new window or tab
  • _self - Opens the linked document in the same window/tab as it was clicked (this is default)
  • _parent - Opens the linked document in the parent frame
  • _top - Opens the linked document in the full body of the window
  • framename - Opens the linked document in a named frame
This example will open the linked document in a new browser window/tab:


Example :


<a href="https://www.webmasterw.com/" target="_blank">Visit W3Schools!</a>

Tip: If your webpage is locked in a frame, you can use target="_top" to break out of the frame:

Example :


<a href="https://www.webmasterw.com/html/" target="_top">HTML5 tutorial!</a>

HTML Links - Image as Link

It is common to use images as links:


Example :


<a href="default.asp">
  <img src="smiley.gif" alt="HTML tutorial" style="width:42px;height:42px;border:0;">
</a>



Note: border:0; is added to prevent IE9 (and earlier) from displaying a border around the image (when the image is a link).



Link Titles

The title attribute specifies extra information about an element. The information is most often shown as a tooltip text when the mouse moves over the element.

Example :


<a href="https://www.webmasterw.com/html/" title="Go to W3Schools HTML section">Visit our HTML Tutorial</a>

HTML Links - Create a Bookmark

HTML bookmarks are used to allow readers to jump to specific parts of a Web page.

Bookmarks can be useful if your webpage is very long.

To make a bookmark, you must first create the bookmark, and then add a link to it.

When the link is clicked, the page will scroll to the location with the bookmark.

Example

First, create a bookmark with the id attribute:


<h2 id="C4">Chapter 4</h2>

Then, add a link to the bookmark ("Jump to Chapter 4"), from within the same page:

<a href="#C4">Jump to Chapter 4</a>

Or, add a link to the bookmark ("Jump to Chapter 4"), from another page:


Example :


<a href="html_demo.html#C4">Jump to Chapter 4</a> 

External Paths

External pages can be referenced with a full URL or with a path relative to the current web page.

This example uses a full URL to link to a web page:

Example :


<a href="https://www.webmasterw.com/html/default.asp">HTML tutorial</a>

This example links to a page located in the html folder on the current web site:

Example :


<a href="/html/default.asp">HTML tutorial</a>


This example links to a page located in the same folder as the current page:


Example :


<a href="default.asp">HTML tutorial</a>

Chapter Summary

  • Use the <a> element to define a link
  • Use the href attribute to define the link address
  • Use the target attribute to define where to open the linked document
  • Use the <img> element (inside <a>) to use an image as a link
  • Use the id attribute (id="value") to define bookmarks in a page
  • Use the href attribute (href="#value") to link to the bookmark








Posted by at No comments:
Subscribe to: Posts (Atom)