Trouble with Internet Explorer

The purpose of this article is to establish an uniform convention to deal with a very special issue of IE. It is for sure without this convention, websites would still run with or without problem. The issue is when IE passing null value from JavaScript to PHP, null value becomes string "null". If there is a possibility the user input could be "null", such as using "null" as login name or password, there is no way for PHP to detect which "null" is null and which "null" is input "null".

So, the accurate solution is never let JavaScript passing null to PHP, but using '' instead. It sounds easy; but JavaScript can generate null value without your knowledge. That is, if a parameter passing through a function to feed a form, when original parameter is undefined, eventually that undefined would be become string "null" or string "undefined" at the end of PHP. So, you would need to deal with every form input by special arrangement as follows:

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

Then, to test if it is valid in JavaScript would be changed to:

; if (''!=parameter) {...}

At PHP end, it is relatively easy to detect if it is a valid input:

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

However, for numeric data, it is not suitable to use '' instead null. It is still suggested to code as usual. The only difference is at PHP end:

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


http://koncordpartners.blogspot.com/2009/12/test-various-nothings-in-php.html

Number of Elements of Array

Number of elements of array is very usual, which can be used as control for the loop or other purposes. Function to get it in JavaScript is varArray.length. In PHP it is count($ varArray) or sizeof($ varArray). Since sizeof() is just an alias of count(), it is suggested using count(), since sizeof() has other meaning in other languages.

The problem happens when array is undefined/not exist. In JavaScript .length would generate a fatal error. So, for save play, it is suggested always using follow codes:

var len = 0;
if ('undefined'!=typeof(varArray)) len = varArray.length;

In PHP count() would generate a return value of 0 together with a non-fatal error message, which would cause even more serious problem because of its non-fatal nature. Fortunately, PHP provides an easy non-fatal error message suppress method “@”:

@count($varArray);

It is very useful because it enables you to always associate @ with count(). And please do so.

For multidimensional array, the usage will be exactly same; and can be used for particular dimension, such as varArray[i] or $varArray[i].