Get Selected Item in JavaScript Form

Somehow JavaScript mixed objects with attributes. For instance:

document.formName.listBoxName[i].selected

formName and listBoxName are references to two bojects. It might be good, but it just crosses the boundary of reference to object and the attributes. Don't know if this the the reason, to get selected item's value in form seems not easy. Google search shows there are so many people ask the question and not get right answers. Here is the easier way:

; function getValueOfSelectedItem(obj)
{ ; var val = obj.options[obj.selectedIndex].value
; if (val) (use val here)
}

To call this function, put the caller on onchange in HTML codes:

onChange="getValueOfSelectedItem(this)"

The beauty of it is there is no mixture of reference and attribute and you can pass anything of it without worry of crossing boundary issue.


http://www.java2s.com/Code/JavaScriptReference/Javascript-Properties/selectedIndexExample.htm

Turning SSRS Report Into Form

The difference between report and form is report pulls data out from database and the form is used to feed data into database. SQL Server Reporting Services is of the report. However, sometimes the two-way interactions are really needed. Here is an example. A parameter need to be input by user; however, if the user had input previously, it should be stored in database and no longer require user to input again.

The logic of the solution is:

1. Get value A of the subject from database according to other parameters.
2. If (Null!=A) then show report based on A, and exit.
3. Else if user input parameter B, then insert B into database, then show report based on B, and exit.
4. Else show the blank report with notice that user needs to key-in the B.

However, this logic does not allow front end to alter the what was already in database. Any change will be manully operated by back end. Alternatively, following logic can be applied:

1. If user input parameter B, then insert or alter B in database, then show report based on B, and exit.
2. Else get value A of the subject from database according to other parameters.
3. If (Null!=A) then show report based on A, and exit.
4. Else show the blank report with notice that user needs to key-in the B.

As a standard procedure, the user therefore is not required to key-in the parameter unless is notified.

INSERT and SET query can be as text or as stored procedure. However, INSERT query should not be stand along as text, or an error message will be generated. At the end, SSRS is of report.

Form And Table In HTML

In general, entire form must be completely included into a single table cell (single TD element). For format purpose, one might put form head/declaration outside the table and input items spread over cells. Put entire form with in a table but spread over several rows (TR elements), it will fail.

In addition, if one uses DHTML, form outsider table may not work in some browser, such as IE.

Conclusion: Put entire form completely with in a single table cell will be the best practice.


http://www.cs.tut.fi/~jkorpela/forms/tables.html

is_int() and is_string() Do Not Work As Expected In PHP

is_int() returns TRUE if the variable passed in is an integer, which may sound similar to is_numeric(). However, data passed in through a form or from MySQL query, even if numeric in content, is of type string, which means that is_int() will fail. Is_numeric(), on the other hand, returns true if the variable is a number or if it is a string containing a number also. This same problem applies to is_float(), as floating-point values set from user input are typed as strings. On contrast, when numeric data passed through a form or from MySQL query, is_string() does return TRUE.

This feature makes is_int() and is_string() next to useless.


http://www.tuxradar.com/practicalphp/7/7/3

Code Conventions: JavaScript

Organizing

There can be six major parts:

1. Passing Variable Register: This is to register any variable across the HTML files. Do not use crossing file variable directly in body of JavaScript, instead declare here. For instance:

; var localVar = parent.superVar

2. Passing Function Register: To register the functions calling other functions located in different HTML file. Do not call crossing file function directly in body of JavaScript, instead declare here. For instance:

; function closeProcess()
{
; parent.closing()
}

Put Passing Variable Register and Passing Function Register at top of JavaScript file to enable easier updating during coding phrase.

3. Local Global Variable Declaration.

4. Event Functions: Include all event functions here, such as onload, etc.

5. HTML Action Functions: If the function is called by HTML file, initialized by the user, it should be included here.

6. Internally Called Functions: Functions called by event functions or action functions.

End of Statement

JavaScript allows the developer to decide whether or not to end a line with a semicolon. If the semicolon is not provided, JavaScript considers the end of the line as the end of the statement. It is suggested to use semicolon instead of nature line break. Furthermore, you can indeed use semicolon in front of each statement, not only emphasis the line break, but also to increase visual impact on the indentation. All examples in this post are in this format.

Comments

It is suggested to use closed comments tag as much as possible: <!-- -->. By doing this, it would be relatively easier to keep coding parts clearer. In addition, if you are using PHP Wrapping JavaScript Debugging Method, as introduced here:
http://koncordpartners.blogspot.com/2010/04/how-to-enforce-download-of-javascript.html, it is essential to use the closed comments.

DHTML

Use + to concatenate every line of HTML codes, such as:

; var htmlBody = ''
+ ' <table> ...
+ ' <tr> ...

Whitespace within string serves no purpose for HTML. However, it can make visual alignment for coding purpose.

Function Declaration

Always use most orthdox variablized function declaration:

; funcation func()
{
...
}

Avoid to use variablized function declaration like var func = function() {...}, unless it is necessary. If you do use variablized function declaration, make sure it had been placed before the caller. For details please see http://koncordpartners.blogspot.com/2010/04/function-declaration-in-javascript.html.

Form With PHP Behind

Use '' instead of null. Accordingly, the PHP end should be:

if (0!=strlen(trim(@$_POST["theInputItem"]))) {...};

When use function to assign value to form, string parameter would need to be assigned with '' in consideration of it might be null or undefined:

; document.theForm.theInputItem.value = (parameter) ? parameter : ''

For details, please refer to http://koncordpartners.blogspot.com/2010/04/trouble-with-internet-explorer.html.


http://javascript.crockford.com/code.html

Multiple Forms in HTML

If there are more than one form in HTML, give every input item a global unique id and name. Else, PHP won’t be able to pick up right item, although you might put input item in right order in HTML.