Different Types of Selection Screens
1. at selection-screen on field
2. at selection-screen output
3. at selection-screen block
4. at selection-screen on value-request
5. at selection-screen on help-request and their difference?
For knowing Selection-screens:
First you must have right understanding of Events.
– Events are introduced by Event Keyword. They end when again next processs begins.
Selection-screens are special screen defined in ABAP.
– This ABAP at run time only controls the flow logic of Selection-screens. The PBO and PAI triggers the num of. selection-screens.
The basic form of the selection screen events is the AT SELECTION-SCREEN event. This event occurs after the runtime environment has passed all input data from the selection screen to the ABAP program. The other selection screen events allow programmers to modify the selection screen before it is sent and specifically check user input.
At Selection-screen OUTPUT is trigerred in PBO of selection-screen.
– This allows you to modify the Selection-screen, before it is displayed.
At Selection-screen On Field is triggered in PAI of selection-screens.
– The input fields can b checked,in the corresponding event block. If an error message occurs within this event block, the corresponding field is made ready for input again on the selection screen.
At Selection-screen On Block is trigerred in PAI event.
– You define a block by enclosing the declarations of the elements in the block between the statements SELECTION-SCREEN BEGIN OF BLOCK block – END OF BLOCK block. You can use this event block to check the consistency of the input fields in the block.
At Selection-screen On value request.
– This event is trigerred for F4 help.
At Selection-screen On help request .
– This event is triggered when the user clicks F1 for help on fileds.
When should we go for inner joins and when for all entries?? basic explanation is given below..
say if u want to display material and its text. u can use this concept.
~from the master table i’m selecting the materials based on the input s_matnr.
~then for the materials selected above , i have to get their corresponding description.
select matnr from mara into table i_matnr
where matnr in s_matnr.
if sy-subrc = 0.
select matnr maktx
from makt into table i_makt
for all entries in i_matnr
where matnr = i_mara-matnr.
This is similar to INNER JOIN concept. get the common data from 2 tables based on the input. Sometimes Join will give poor performance , n there u can use FOR ALL ENTRIES.
Joins have the advantage of linking two or more tables based on few of the conditions.However, there are a few disadvantages with same.
1) Duplicates are removed from the resulting set.Hence proper care has to be taken for the unique fields and keys that are used to determine the result.
2)If the resulting table is going to be very large, performace can be well affected.
It is in this scenario , we use “for all entries“.The strategy would be to obtain the results for first table and based on the entries of first table, second table is filled and so on.But if the table on which the For All Entries IN clause is based is empty, all rows are selected into the destination table. Hence it is advisable to check before-hand that the first table is not empty.
For more: http://help.sap.com/abapdocu_702/en/abenwhere_logexp_itab.htm
HTML5 has introduced many new APIs and have extended, changed or obsoleted some existing APIs.
5.1 New APIs
HTML5 introduces a number of APIs that help in creating Web applications. These can be used together with the new elements introduced for applications:
- Media elements (
audio) have APIs for controlling playback, syncronising multiple media elements, and timed text tracks (e.g. subtitles).
- An API for form constraint validation (e.g. the
- An API for commands that the user can invoke (used together with the
command element among others).
- An API that enables offline Web applications, with an application cache.
- An API that allows a Web application to register itself for certain protocols or media types, using
- Editing API in combination with a new global
- Drag & drop API in combination with a
- An API that exposes the components of the document’s URL and allows scripts to navigate, redirect and reload (the
- An API that exposes the session history and allows scripts to update the document’s URL without actually navigating, so that applications don’t need to abuse the fragment component for “Ajax-style” navigation (the
- An API for base64 conversion (
- An API to schedule timer-based callbacks (
- An API to prompt the user (
- An API for printing the document (
- An API for handling search providers (
Window object has been defined.
WHATWG HTML has further APIs that are not in HTML5 but are separate specifications at the W3C:
5.2 Changed APIs
The following features from DOM Level 2 HTML are changed in various ways:
document.title now collapses whitespace on getting.
document.domain is made settable, which can change the document’s effective script origin.
document.open() now either clears the document (if invoked with two or less arguments), or acts like
window.open() (if invoked with three or four arguments). In the former case, throws an exception in XML.
document.writeln() throw an exception in XML. The latter two now support variadic arguments; they can add text to the document’s input stream while it is still being parsed, or can imply a call to
document.open() or be ignored altogether in some cases.
document.getElementsByName() now returns all HTML elements with a
name attribute matching the argument.
HTMLFormElement now returns an
length returns the number of nodes in
HTMLSelectElement now also accepts an integer as its second argument.
HTMLSelectElement now removes the first element in the collection if the argument is out of bounds.
area elements now stringify to their
blur() methods are now available on all HTML elements.
Several attributes have changed in various ways.
accept attribute on
input now allows the values
accesskey global attribute now allows multiple characters to be specified, which the user agent can choose from.
action attribute on
form is no longer allowed to have an empty URL.
- In WHATWG HTML, the
method attribute has a new keyword
dialog, intended to close a
border attribute on
table only allows the values “1” and the empty string. In WHATWG HTML, the
border attribute is obsolete.
colspan attribute on
th now has to be greater than zero.
coords attribute on
area no longer allows a percentage value of the radius when the element is in the circle state.
data attribute on
object is no longer said to be relative to the
defer attribute on
script now explicitly makes the script execute when the page has finished parsing.
dir global attribute now allows the value
enctype attribute on
form now supports the value
height attributes on
object are no longer allowed to contain percentages. They are also not allowed to be used to stretch the image to a different aspect ratio than its intrinsic aspect ratio.
href attribute on
link is no longer allowed to have an empty URL.
href attribute on
base is now allowed to contain a relative URL.
- All attributes that take URLs, e.g.
href on the
a element, now support IRIs if the document’s encoding is UTF-8 or UTF-16.
http-equiv attribute on
meta is no longer said to be used by HTTP servers to create HTTP headers in the HTTP response. Instead, it is said to be a pragma directive to be used by the user agent.
id global attribute is now allowed to have any value, as long as it is unique, is not the empty string, and does not contain space characters.
lang global attribute takes the empty string in addition to a valid language identifier, just like
xml:lang does in XML.
media attribute on
link now accepts a media query and defaults to “all”.
- The event handler attributes (e.g.
value attribute of the
li element is no longer deprecated as it is not presentational. The same goes for the
type attributes of the
style global attribute now always uses CSS as the styling language.
tabindex global attribute now allows negative values which indicate that the element can receive focus but cannot be tabbed to.
target attribute of the
area elements is no longer deprecated, as it is useful in Web applications, e.g. in conjunction with
type attribute on
usemap attribute on
img no longer takes a URL, but instead takes a valid hash-name reference to a
The following attributes are allowed but authors are discouraged from using them and instead strongly encouraged to use an alternative solution:
border attribute on
img. It is required to have the value “
0” when present. Authors can use CSS instead.
language attribute on
script. It is required to have the value “
type attribute. Authors can simply omit it as it has no useful function.
name attribute on
a. Authors can use the
id attribute instead.
These elements have slightly modified meanings in HTML5 to better reflect how they are used on the Web or to make them more useful:
address element is now scoped by the nearest ancestor
b element now represents a span of text to which attention is being drawn for utilitarian purposes without conveying any extra importance and with no implication of an alternate voice or mood, such as key words in a document abstract, product names in a review, actionable words in interactive text-driven software, or an article lede.
cite element now solely represents the title of a work (e.g. a book, a paper, an essay, a poem, a score, a song, a script, a film, a TV show, a game, a sculpture, a painting, a theatre production, a play, an opera, a musical, an exhibition, a legal case report, etc). Specifically the example in HTML4 where it is used to mark up the name of a person is no longer considered conforming.
dl element now represents an association list of name-value groups, and is no longer said to be appropriate for dialogue.
hr element now represents a paragraph-level thematic break.
i element now represents a span of text in an alternate voice or mood, or otherwise offset from the normal prose in a manner indicating a different quality of text, such as a taxonomic designation, a technical term, an idiomatic phrase from another language, a thought, or a ship name in Western texts.
- For the
label element the browser should no longer move focus from the label to the control unless such behavior is standard for the underlying platform user interface.
menu element is redefined to be useful for toolbars and context menus.
noscript element is no longer said to be rendered when the user agent doesn’t support a scripting language invoked by a
script element earlier in the document.
s element now represents contents that are no longer accurate or no longer relevant.
script element can now be used for scripts or for custom data blocks.
small element now represents side comments such as small print.
strong element now represents importance rather than strong emphasis.
u element now represents a span of text with an unarticulated, though explicitly rendered, non-textual annotation, such as labeling the text as being a proper name in Chinese text (a Chinese proper name mark), or labeling the text as being misspelt.
Several attributes have been introduced to various elements that were already part of HTML4:
area elements now have a
media attribute for consistency with the
link element. WHATWG HTML also has the
area element, for consistency with the
link elements, now also has the
base element can now have a
target attribute as well, mainly for consistency with the
a element. (This is already widely supported.)
meta element has a
charset attribute now as this was already widely supported and provides a nice way to specify the character encoding for the document.
- A new
autofocus attribute can be specified on the
input (except when the
type attribute is
button elements. It provides a declarative way to focus a form control during page load. Using this feature should enhance the user experience compared to focusing the element with script as the user can turn it off if the user does not like it, for instance.
- A new
placeholder attribute can be specified on the
textarea elements. It represents a hint intended to aid the user with data entry.
<input type=email placeholder="email@example.com">
- The new
form attribute for
fieldset elements allows for controls to be associated with a form. These elements can now be placed anywhere on a page, not just as descendants of the
form element, and still be associated with a
<td><form id=1><input name=1-key></form>
<td><input form=1 name=1-value>
<td><button form=1 name=1-action value=save>✓</button>
<button form=1 name=1-action value=delete>✗</button>
- The new
required attribute applies to
input (except when the
type attribute is
image or some button type such as
textarea. It indicates that the user has to fill in a value in order to submit the form. For
select, the first
option element has to be a placeholder with an empty value.
<label>Color: <select name=color required>
<option value="">Choose one
fieldset element now allows the
disabled attribute which disables all descendant controls (excluding those that are descendants of the
legend element) when specified, and the
name attribute which can be used for script access.
input element has several new attributes to specify constraints:
step. As mentioned before it also has a new
list attribute which can be used together with the
datalist element. It also now has the
height attributes to specify the dimensions of the image when using
textarea elements have a new attribute named
dirname that causes the directionality of the control as set by the user to be submitted as well.
textarea element also has two new attributes,
wrap which control max input length and submitted line wrapping behavior, respectively.
form element has a
novalidate attribute that can be used to disable form validation submission (i.e. the form can always be submitted).
button elements have
formtarget as new attributes. If present, they override the
target attributes on the
- In WHATWG HTML, the
textarea have an
menu element has two new attributes:
label. They allow the element to transform into a menu as found in typical user interfaces as well as providing for context menus in conjunction with the global
style element has a new
scoped attribute which can be used to enable scoped style sheets. Style rules within such a
style element only apply to the local tree.
script element has a new attribute called
async that influences script loading and execution.
html element has a new attribute called
manifest that points to an application cache manifest used in conjunction with the API for offline Web applications.
link element has a new attribute called
sizes. It can be used in conjunction with the
icon relationship (set through the
rel attribute; can be used for e.g. favicons) to indicate the size of the referenced icon. Thus allowing for icons of distinct dimensions.
ol element has a new attribute called
reversed. When present, it indicates that the list order is descending.
iframe element has three new attributes called
srcdoc which allow for sandboxing content, e.g. blog comments.
object element has a new attribute called
typemustmatch which allows safer embedding of external resources.
img element has a new attribute called
crossorigin to use CORS in the fetch and if it is successful, allows the image data to be read with the
canvas API. In WHATWG HTML, there is also a new attribute called
srcset to support multiple images for different resolutions and different images for different viewport sizes.
Several attributes from HTML4 now apply to all elements. These are called global attributes:
title. Additionally, XHTML 1.0 only allowed
xml:space on some elements, which is now allowed on all elements in XHTML documents.
There are also several new global attributes:
contenteditable attribute indicates that the element is an editable area. The user can change the contents of the element and manipulate the markup.
contextmenu attribute can be used to point to a context menu provided by the author.
data-* collection of author-defined attributes. Authors can define any attribute they want as long as they prefix it with
data- to avoid clashes with future versions of HTML. These are intended to be used to store custom data to be consumed by the Web page or application itself. They are not intended for data to be consumed by other parties (e.g. user agents).
dropzone attributes can be used together with the new drag & drop API.
hidden attribute indicates that an element is not yet, or is no longer, relevant.
- WHATWG HTML has the
inert attribute, intended to make
dialog elements modal.
aria-* collection attributes which can be used to instruct assistive technology.
spellcheck attribute allows for hinting whether content can be checked for spelling or not.
translate attribute gives a hint to translators whether the content should be translated.
HTML5 also makes all event handler attributes from HTML4, which take the form
onevent, global attributes and adds several new event handler attributes for new events it defines. For instance, the
onplay event handler attribute for the
play event which is used by the API for the media elements (
Lets see briefly what is the difference between HTML4 & HTML5 today…
Before get into deep of html5 lets look into some basics.. 😉
Do u know what is doctype and why its used??
The HTML syntax of HTML5 requires a doctype to be specified to ensure that the browser renders the page in standards mode. The doctype has no other purpose.
In order to deal both with content written according to Web standards and with content written according to legacy practices that were prevalent in the late 1990s, today’s Web browsers implement various engine modes.
Names of Browser Engines
|Internet Explorer 4…7
|Mac IE 5
||Presto Core 2
- The script engine of Mac IE 5 is a port of the engine that is used in Windows IE although the layout engines are different.
What is HTML5?
HTML5 is the latest version of HTML and XHTML. It comes up with a number of features like drag and drop, multimedia, video playback, APIs, form control etc.
What are the benefits of HTML5?
- HTML5 brings in new elements to structure the web pages as compared to HTML4 which uses common structures such as: – header, columns etc.
- These new elements are: header, nav, section, article, aside, footer etc.
The following elements have been introduced for better structure:
Then there are several other new elements:
type attribute now has the following new values:
The idea of these new types is that the user agent can provide the user interface, such as a calendar date picker or integration with the user’s address book, and submit a defined format to the server. It gives the user a better experience as his input is checked before sending it to the server meaning there is less time to wait for feedback.
For more clickhere