The HTML tables allow web authors to arrange data like text, images, links, other tables, etc. into rows and columns of cells.
The HTML tables are created using the <table> tag in which the <tr> tag is used to create table rows and <td> tag is used to create data cells.
Table heading can be defined using <th> tag. This tag will be put to replace <td> tag, which is used to represent actual data cell. Normally you will put your top row as table heading as shown below, otherwise you can use <th> element in any row.
Cellpadding and Cellspacing Attributes
There are two attribiutes called cellpadding and cellspacing which you will use to adjust the white space in your table cells. The cellspacing attribute defines the width of the border, while cellpadding represents the distance between cell borders and the content within a cell.
Colspan and Rowspan Attributes
You will use colspan attribute if you want to merge two or more columns into a single column. Similar way you will use rowspan if you want to merge two or more rows.
Table Height and Width
You can set a table width and height using width and height attrubutes. You can specify table width or height in terms of pixels or in terms of percentage of available screen area.
Images are very important to beautify as well as to depict many complex concepts in simple way on your web page. This tutorial will take you through simple steps to use images in your web pages.
You can insert any image in your web page by using <img> tag. Following is the simple syntax to use this tag.
To try following example, let’s keep our HTML file test.htm and image file test.png in the same directory:
You can use PNG, JPEG or GIF image file based on your comfort but make sure you specify correct image file name in src attribute. Image name is always case sensitive.
The alt attribute is a mandatory attribute which specifies an alternate text for an image, if the image cannot be displayed.
Set Image Location
Usually we keep our all the images in a separate directory. So let’s keep HTML file test.htm in our home directory and create a subdirectory images inside the home directory where we will keep our image test.png.
Assuming our image location is “/html/image/test.png”
Set Image Width/Height
You can set image width and height based on your requirement using widthand height attributes. You can specify width and height of the image in terms of either pixels or percentage of its actual size.
Set Image Border
By default image will have a border around it, you can specify border thickness in terms of pixels using border attribute. A thickness of 0 means, no border around the picture.
Set Image Alignment
By default image will align at the left side of the page, but you can use align attribute to set it in the center or right.
Comment is a piece of code which is ignored by any web browser. It is a good practice to add comments into your HTML code, especially in complex documents, to indicate sections of a document, and any other notes to anyone looking at the code. Comments help you and others understand your code and increases code readability.
HTML comments are placed in between <!– … –> tags. So any content placed with-in <!– … –> tags will be treated as comment and will be completely ignored by the browser.
So far we have seen single line comments, but HTML supports multi-line comments as well.
You can comment multiple lines by the special beginning tag <!– and ending tag –> placed before the first line and end of the last line as shown in the given example below.
HTML lets you specify metadata – additional information about a document in a variety of ways. The META elements can be used to include name/value pairs describing properties of the HTML document, such as author, expiry date, a list of keywords, document author etc.
The <meta> tag is used to provide such additional information. This tag is an empty element and so does not have a closing tag but it carries information within its attributes.
You can include one or more meta tags in your document based on what information you want to keep in your document but in general, meta tags do not impact physical appearance of the document so from appearance point of view, it does not matter if you include them or not.
Adding Meta Tags to Your Documents
You can add metadata to your web pages by placing <meta> tags inside the header of the document which is represented by <head> and </head> tags. A meta tag can have following attributes in addition to core attributes:
You can use <meta> tag to specifyimportant keywords related to the document and later these keywords are used by the search engines while indexing your webpage for searching purpose.
You can use <meta> tag to give a short description about the document. This again can be used by various search engines while indexing your webpage for searching purpose.
Cookies are data, stored in small text files on your computer and it is exchanged between web browser and web server to keep track of various information based on your web application need.
You can use <meta> tag to store cookies on client side and later this information can be used by the Web Server to track a site visitor.
Following is an example of redirecting current page to another page after 5 seconds. If you want to redirect page immediately then do not specify contentattribute.
If you use a word processor, you must be familiar with the ability to make text bold, italicized, or underlined; these are just three of the ten options available to indicate how text can appear in HTML and XHTML.
Anything that appears within <b>…</b> element.
Anything that appears within <i>…</i> element.
Anything that appears within <u>…</u> element.
Anything that appears within <strike>…</strike> element is displayed with strikethrough.
The content of a <tt>…</tt> element is written in monospaced font. Most of the fonts are known as variable-width fonts because different letters are of different widths (for example, the letter ‘m’ is wider than the letter ‘i’). In a monospaced font, however, each letter has the same width.
The content of a <sup>…</sup> element is written in superscript; the font size used is the same size as the characters surrounding it but is displayed half a character’s height above the other characters.
The content of a <sub>…</sub> element is written in subscript; the font size used is the same as the characters surrounding it, but is displayed half a character’s height beneath the other characters.
Anything that appears within <ins>…</ins> element.
Anything that appears within <del>…</del> element.
The content of the <big>…</big> element is displayed one font size larger than the rest of the text surrounding
The content of the <small>…</small> element is displayed one font size smaller than the rest of the text surrounding
We have seen few HTML tags and their usage like heading tags <h1>, <h2>, paragraph tag <p> and other tags. We used them so far in their simplest form, but most of the HTML tags can also have attributes, which are extra bits of information.
An attribute is used to define the characteristics of an HTML element and is placed inside the element’s opening tag. All attributes are made up of two parts: a name and a value:
- The name is the property you want to set. For example, the paragraph <p> element in the example carries an attribute whose name is align, which you can use to indicate the alignment of paragraph on the page.
- The value is what you want the value of the property to be set and always put within quotations. The below example shows three possible values of align attribute: left, center and right.
The four core attributes that can be used on the majority of HTML elements (although not all) are:
The id Attribute
The id attribute of an HTML tag can be used to uniquely identify any element within an HTML page. There are two primary reasons that you might want to use an id attribute on an element:
- If an element carries an id attribute as a unique identifier it is possible to identify just that element and its content.
- If you have two elements of the same name within a Web page (or style sheet), you can use the id attribute to distinguish between elements that have the same name.
The title Attribute
The title attribute gives a suggested title for the element. They syntax for thetitle attribute is similar as explained for id attribute:
The behavior of this attribute will depend upon the element that carries it, although it is often displayed as a tooltip when cursor comes over the element or while the element is loading.
The class Attribute
The class attribute is used to associate an element with a style sheet, and specifies the class of element. You will learn more about the use of the class attribute when you will learn Cascading Style Sheet (CSS). So for now you can avoid it.
The style Attribute
The style attribute allows you to specify Cascading Style Sheet (CSS) rules within the element.
Here’s a table of some other attributes that are readily usable with many of the HTML tags.
An HTML element is defined by a starting tag. If the element contains other content, it ends with a closing tag, where the element name is preceded by a forward slash as shown below with few tags:
||This is paragraph content.
||This is heading content.
||This is division content.
So here <p>….</p> is an HTML element, <h1>…</h1> is another HTML element. There are some HTML elements which don’t need to be closed, such as <img…/>, <hr /> and <br /> elements. These are known as void elements.
HTML documents consist of a tree of these elements and they specify how HTML documents should be built, and what kind of content should be placed in what part of an HTML document.
HTML Tag vs. Element
An HTML element is defined by a starting tag. If the element contains other content, it ends with a closing tag.
For example <p> is starting tag of a paragraph and </p> is closing tag of the same paragraph but <p>This is paragraph</p> is a paragraph element.