Megan Trebilcock

Topic #1: HTML Images

HTML Images Syntax

The HTML /img/ tag is used to embed an image in a web page.

Images are not technically inserted into a web page; images are linked to web pages. The /img/ tag creates a holding space for the referenced image.

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

The /img/ tag has two required attributes:

src - Specifies the path to the image

alt - Specifies an alternate text for the image

Syntax: /img src="url" alt="alternatetext"/

The src Attribute

Note: When a web page loads, it is the browser, at that moment, that gets the image from a web server and inserts it into the page. Therefore, make sure that the image actually stays in the same spot in relation to the web page, otherwise your visitors will get a broken link icon. The broken link icon and the alt text are shown if the browser cannot find the image.

Ex.

The alt Attribute

The required 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:

Ex.

If browser cannot find the image it will display the alt code:

/ alt="Flowers in Chania"

Image Size-width and height

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

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

OR you can use width and height attributes:

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

Width and Height, or Style?

The width, height, and style attributes are all valid in HTML. However, we suggest using the style attribute. It prevents styles sheets from changing the size of images:

ex.

/style/

img {

width: 100%;

}

//style/

/img src="html5.gif" alt="HTML5 Icon" width="128" height="128"/

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

Images in Another Folder

If you have your images in a sub-folder, you must include the folder name in the src attribute:

img src="/images/html5.gif"

Images on Another Server/Website

Some web sites point to an image on another server.

To point to an image on another server, you must specify an absolute (full) URL in the src attribute:

Animated Images

HTML allows animated GIFs:

Image as a Link

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

Image Floating

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

The image will float to the right of the text.

The image will float to the left of the text.

Common Image Formats

Here are the most common image file types, which are supported in all browsers (Chrome, Edge, Firefox, Safari, Opera):

Topic #2: CSS colors

CSS Color Names

In CSS, a color can be specified by using a predefined color name CSS/HTML supports 140 standard color names.

CSS Background Color

You can set the background color for HTML elements:

/*/ instead of <>

/h1 style=*background-color:DodgerBlue;*/my text goes here/p style="background-color:Tomato; my text goes here

CSS Text Color

You can set the color of text:

/h4 style=*color:tomato;*text goes here//h4/

/p style=*color:dodgerblue;*/text goes here//p/

/p style=*color:mediumseagreen;*/text goes here//p/

CSS Border Color

You can set the color of borders:

/h4 style=*border:2px solid Tomato;*/text goes here//h4/

/h4 style=*border:2px solid DodgerBlue;*/text goes here//h4/

/h4 style=*border:2px solid Violet;*/text goes here//h4/

CSS Color Values

In CSS, colors can also be specified using RGB values, HEX values, HSL values, RGBA values, and HSLA values:

Same as color name "Tomato":

rgb(255,99,71)

(#ff6347)

hsl(9,100%,64%)

Same as color name "Tomato", but 50% transparent:

rgba(255,99,71,0.5)

hsla(9,100%,64%,0.5)

Topic #3: CSS backgrounds

CSS background-color

The background-color property specifies the background color of an element.

body {

background-color: lightblue;

}

With CSS, a color is most often specified by:

a valid color name - like "red"

a HEX value - like "#ff0000"

an RGB value - like "rgb(255,0,0)"

Look at CSS Color Values for a complete list of possible color values.

Other Elements

You can set the background color for any HTML elements:

Example

h4 {

background-color: green;

}

div {

background-color: lightblue;

}

p {

background-color: yellow;

}

Opacity / Transparency

The opacity property specifies the opacity/transparency of an element. It can take a value from 0.0 - 1.0. The lower value, the more transparent:

div {

background-color: green;

opacity: 0.3;

}

Transparency using RGBA

If you do not want to apply opacity to child elements, like in our example above, use RGBA color values. The following example sets the opacity for the background color and not the text:

div {

background: rgba(0, 128, 0, 0.3) /* Green background with 30% opacity */

}