Validate given string is JSON

function isJson(str) {
    try {
        JSON.parse(str);
    } catch (e) {
        return false;
    }
    return true;
}

Convert a JavaScript Object to FormData Object

/* takes a {} object and returns a FormData object */
function objectToFormData(obj, form, namespace) {
    var fd = form || new FormData();
    var form_key;
    for (var property in obj) {
        if (obj.hasOwnProperty(property) && property != '$$hashKey') {
            if (namespace) {
                form_key = namespace + '[' + property + ']';
            } else {
                form_key = property;
            }
            /*if the property is an object, but not a File,*/
            /*use recursivity.*/
            if (obj[property] instanceof Date) {
                fd.append(form_key, obj[property].toISOString());
            } else if (typeof obj[property] === 'object' && !(obj[property] instanceof File)) {
                objectToFormData(obj[property], fd, form_key);
            } else {
                /*if it's a string or a File object*/
                if (!empty(obj[property])) {
                    fd.append(form_key, obj[property]);
                }
            }
        }
    }
    return fd;
}

Check given variable is Empty ?

/* check variable contain empty values or not */
function empty(data) {
    if (typeof(data) == 'number' || typeof(data) == 'boolean') {
        return false;
    }
    if (typeof(data) == 'undefined' || data === null) {
        return true;
    }
    if (typeof(data.length) != 'undefined') {
        /*if(/^[\s]*$/.test(data.toString())) {
        return true;
        }*/
        return data.length == 0;
    }
    if (data instanceof File) {
        return false;
    }
    var count = 0;
    for (var i in data) {
        /* if (data.hasOwnProperty(i)) { */
        count++;
        /* } */
    }
    return count == 0;
}

Send Post Request without response

function post_without_wait12($url, $params)
{               
    foreach ($params as $key => &$val) {
        if (is_array($val)) $val = implode(',', $val);
        $post_params[] = $key.'='.urlencode($val);
    }
   
    $post_string = implode('&', $post_params);
   
    $parts=parse_url($url);
    $fp = fsockopen($parts['host'],
    isset($parts['port'])?$parts['port']:80,
    $errno, $errstr, 30);
    $out = "POST ".$parts['path']." HTTP/1.1\r\n";
    $out.= "Host: ".$parts['host']."\r\n";
    $out.= "Content-Type: application/x-www-form-urlencoded\r\n";
    $out.= "Content-Length: ".strlen($post_string)."\r\n";
    $out.= "Connection: Close\r\n\r\n";
    if (isset($post_string)) $out.= $post_string;
    fwrite($fp, $out);
    fclose($fp);
}

Is PHP Session Start ?

if ( pk_is_session_started() === FALSE ) session_start();


function pk_is_session_started()
{
    if ( php_sapi_name() !== 'cli' ) {
        if ( version_compare(phpversion(), '5.4.0', '>=') ) {
            return session_status() === PHP_SESSION_ACTIVE ? TRUE : FALSE;
        } else {
            return session_id() === '' ? FALSE : TRUE;
        }
    }
    return FALSE;
}

WordPress Check Dependent Plugin Is Installed ?

register_activation_hook( __FILE__, 'pkLm_plugin_activate' );
function pkLm_plugin_activate(){
    // Require parent plugin
    if ( ! is_plugin_active( `'plugin_folder/plugin_file'` ) and current_user_can( 'activate_plugins' ) ) {
        // Deactivate the plugin
        deactivate_plugins(__FILE__);
    
        // Throw an error in the wordpress admin console
        $error_message = __('This plugin requires <a href="#">`Dependent Plugin Name`</a> plugin to be active!');
        die($error_message);
    }
} 

Remove index.php from URL

RewriteEngine on
RewriteCond $1 !^(index\.php|resources|robots\.txt)
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.*)$ index.php/$1 [L,QSA]