CodeHelp - glossary A

Abbreviations used within documents can be marked with the <abbr></abbr> tag to make your documents available to a wider web audience, especially text-to-speech conversion browsers. Use the title attribute to give the full version. e.g.. <abbr title="for example">e.g.</abbr> See also Acronym.
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• In relation to links and URL's:
  An absolute URL is independent of where the current document is located on your system or your web server. Absolute URL's are required for external sites and need to include everything from the http onwards.e.g. http://www.codehelp.co.uk or www.codehelp.co.uk/query/past.html are both absolute URL's. These links remain active if the current document is moved. See also relative.
• In relation to CSS positioning:
  Absolute positioning is used for elements that would be out of place if allowed to flow with the surrounding elements. e.g. The background on the CodeHelp site uses absolute positioning to eliminate the border that would appear if the image was placed with relative positioning, even as the first line of the body section. Use relative to provide access with Javascript without affecting the position of the element relative to the rest of the page. (The default in HTML is static positioning and Javascript requires the use of the relative position attribute to access the element. Changing the setting to relative from static does not affect the position of the element itself.)

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See also Abbreviation. Use <acronym></acronym> to enclose all acronyms used within the text of your documents to make your pages accessible to the widest audience. Add a title attribute and the browser will explain the acronym for you when the mouse hovers over the acronym. Examples: DHTML, CSS, HTML, WWW. Netscape4 does not support this useful feature, Netscape6 does.
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attribute: See also Forms. The action="" attribute in the <form> tag tells the browser where it can find the program that will process the information gathered by the form. Absolute or relative URL's can be used but make sure you have 'permission' or access to the program before using the form. Generally, the action attribute points to a CGI script resident on the same system as your site. Ask your ISP for details of scripts like formmail which translate the data from the form into an email that is sent to your usual email address. These scripts often require you to add certain fields (that can be hidden from the form) to tell the program who you are and where you can be reached.
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<address></address>

Generally displays the ownership or address of the page author in italic type with a line break above and below. Like <abbr>, this can also increase the accessibility of your pages to those with text to speech conversion browsers.
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Alternative Text - a required (HTML4) attribute of the <img> tag. alt="" should contain text that briefly describes the image or the page to which the image is linked if the <img> tag is contained within the <a></a> tag.
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Use to anchor or base a link. You can link to an internal page on your site or an external page anywhere on the net. Links to external pages are absolute references - the full path must be specified. Links to internal pages can be absolute or relative: files in the same directory on your site can be linked using just the filename (with extension; htm or html) files in sub-directories linked using the name of the directory (dir/file.htm) and files in directories above the current document use two dots to specify the immediate parent: (../file.htm) Link to pages using <a href="URL">Link_Text</a> Always use </a> to close an anchor tag - or the whole document may become part of your link and some sections will not display at all.
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• Constructor
  Create an empty array of undefined size.
  var my_array = new Array();
  
  Create an empty array of length size
var size=5;
var my_array = new Array(size);
  
  Create an array with defined elements.
  var my_array = new Array("a","b","c", . . . . )
  
  
• Properties
  To obtain the length of an array (the number of elements)
  var size=my_array.length;
  
  
• Methods
  Join all the elements of an array into a single string with commas between elements:
  var string = my_array.join("-");
  
  Remove and return the last element in an array:
  var value = my_array.pop();
  
  Push a new value onto the end of an array:
  my_array.push("new");
  
  Reverse all elements in an array:
  my_array.reverse();
  
  Remove first element from array and shift all array elements up one:
  my_array.shift();
  
  Return only a portion of the array, slice() takes two arguments, a start value and an end value. The start value must not be equal or less than the end value. To slice out only the second value :
  my_array.slice(2,3);
  
  Sort the elements of an array :
  my_array.sort();
  
  Insert, remove or replace array elements in one operation To start removal at element one, remove one element and insert an item "old" :
  my_array.splice(1,1,"old");
  
  Convert entire array to a string - unlike join, there is no facility to change the separator character used to separate array values in the final string.
  my_array.toString();
  
  Insert a new value at the beginning of the array and move other values down. Return value may be undefined in IE:
  my_array.unshift("test");

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Standard alphanumeric characters (a to z and 0 to 9). Usually taken to include some special characters like punctuation marks, brackets, simple arithmetic symbols. ASCII files are sometimes known as "text" files.
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Additional information added to a tag to modify the effect of the tag on the document. Some tags are optional, some are required. e.g. <a href=""> the href="" entry is an attribute, it tells the <a> tag that the anchor is to serve as a link to another source, and the contents (or value) of the attribute give the location of the linked data. The <img> tag has a required attribute of src="" which tells the browser where to find the image to insert into the document in place of the <img> tag.
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The <au></au> tag can be used to mark out the author of the page for text to speech browsers or as a feature within CSS. Unfortunately, <au> is not formally part of HTML4 and will not validate. Use the alternative meta tag.
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