protected function _mergeAttr(array $attrs = array(), $val = null, $key = 'class')
    {
        if (Arr::key($key, $attrs)) {
            $attrs[$key] .= ' ' . $val;
        } else {
            $attrs[$key] = $val;
        }
        return $attrs;
    }
protected function _mergeAttr(array $attrs = array(), $val = null, $key = 'class')
    {
        if (Arr::key($key, $attrs)) {
            $attrs[$key] .= ' ' . $val;
        } else {
            $attrs[$key] = $val;
        }
        return $attrs;
    }
protected function _mergeAttr ( array $ attrs = array ( ) , $ val = null , $ key = 'class' ) { if ( Arr :: key ( $ key , $ attrs ) ) { $ attrs [ $ key ] .= ' ' . $ val ; } else { $ attrs [ $ key ] = $ val ; } return $ attrs ; }
Merge attributes by given key.

@param array $attrs
@param null $val
@param string $key
@return array
Merge attributes by given key .