how to check element visibility in jquery?

example of element exists and it’s not visible

<div id="test">
  <div id="test_1" style="display:none">
    Hello World!
  </div>
</div>


jQuery code:
  if ($('#test_1:visible').length > 0)
{
         alert('the element is visible');
}
    else
{
         alert('the element is not visible');
}

how to replace & or special characters in javascript?

//if  value of catnm='art & jewllery';

//then i want need to replace "&".

//because when i will try to post data using jquery then jquery know this is query string.....so i want to need  to replace "&"  using "URL ENCODED CHARACTERS"

//so,see below example

var catnm=document.getElementById('catnm').value;

var cat_re=catnm.replace('&','%26');

OUTPUT 

In Javascript alert box  : art %26 jewllery

In html format(in web browser )  : art & jewllery

Please refer below website for URL Encode Characters

http://www.degraeve.com/reference/urlencoding.php

http://www.w3schools.com/tags/ref_urlencode.asp

how to validate multiple select box with jquery?

$("#form").validate({
rules:{
"select_esp[]": "required"
},
messages:{
"select_esp[]": "Select this"
}
});

 

How to enable/disable element in Javascript

If u want to enable or disable any HTML element using javascript in asp.net/php u can use the following code,

document.getelementbyid('nm').disabled='disabled' ;


and the below code will enable the element,

document.getelementbyid('nm').disabled='';

Sql Joins

how to make captcha in php?

Captcha Code:

<?php
session_start();

$num='';

$string = "abcdefghijklmnopqrstuvwxyz0123456789";
for($i=0;$i<7;$i++){
$num1=rand(0,35);
$num .= $string{$num1};
}

$_SESSION["num1"]=$num;

$img=imagecreatefrompng('captcha.png');
$color=imagecolorallocate($img,255,255,255);
$color1=imagecolorallocate($img,0,0,0);
imagestring($img,9,10,3,$num,30);
$fontsize=20;
$fontcolor = imagecolorallocate($img, 0, 0, 0);
$x = 0;
$y = $fontsize;

header('Content-type : image/png');
imagepng($img);
imagedestroy($img);

?>

How to use in php?

<img id="cap" style="margin-left: 15px;" src="comman/captcha.php" alt="" />

How to refresh captcha?

Call the below function  onclick

<script >
function captcha()
{
document.getElementById('cap').src = document.getElementById('cap').src+ '?';
}
</script>

Save as captcha.png file

how to check path of ffmpeg or mencoder in linux in php?

<?php
$output = shell_exec('whereis ffmpeg');
echo "<pre>".$output."</pre>";
echo "";

$output = shell_exec('whereis mencoder');
echo "<pre>".$output."</pre>";
echo "";
?>

Output in browser :