Code lab for HTML, CSS, PHP, Javascript and more.

Selection sort works by finding the smallest item in the array and exchange in with the first entry. Then, find the next smallest item and exchange in with the second entry, which continue till all array is sorted.

Selection sorting takes (N*N)/2 running time to sort N items.

Tuterial video (more…)

This article will try to explain the basic idea about memory used by Primitive data type and some data structure in Java implementation.

Primitive data types

• boolean 1 byte
• byte 1 byte
• char 2 bytes
• int 4 bytes
• float 4 bytes
• long 8 bytes
• double 8 bytes

• overhead 16 bytes // overhead includes a reference to the object’s class, garbage collection information and synchronization information
• padding 4 bytes // memory uses padded on a 64-bit machine
• reference 8 bytes // reference to different object or data type

Object : Memory used by an object is equal to the memory used by each instance + overhead (16 bytes) + padding (4 bytes). For example

private class ageGender
{
int age=0;
char gender = ''; //"m" for male and "f" for female
}

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Javascript code using AJAX XmlHttpRequest. “send()” function can be executed using normal javascript function call, passing one argument to be sent to send.php through POST.

//Function creating XmlHttpObject
function GetXmlHttpObject(){
var xmlHttp=null;
try{
// Firefox, Opera 8.0+, Safari
xmlHttp=new XMLHttpRequest();
}
catch (e){
// Internet Explorer
try{
xmlHttp=new ActiveXObject("Msxml2.XMLHTTP");
}
catch (e){
xmlHttp=new ActiveXObject("Microsoft.XMLHTTP");
}
}
return xmlHttp;
}

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It is possible to pre-define the form input type according to its validation rule using HTML5. This use will will validate the input data with out the use of custom code.
There are 7 different types of input type email, url, number, range, date pickers, search and color.

As in the example below <input> type is set to “email” and required attribute is set to “required“. (more…)