framework/base/View.php
public function renderDynamic($statements)
    {
        if (!empty($this->cacheStack)) {
            $n = count($this->dynamicPlaceholders);
            $placeholder = "<![CDATA[YII-DYNAMIC-$n]]>";
            $this->addDynamicPlaceholder($placeholder, $statements);

            return $placeholder;
        }

        return $this->evaluateDynamicContent($statements);
    }
public function renderDynamic($statements)
    {
        if (!empty($this->cacheStack)) {
            $n = count($this->dynamicPlaceholders);
            $placeholder = "<![CDATA[YII-DYNAMIC-$n]]>";
            $this->addDynamicPlaceholder($placeholder, $statements);

            return $placeholder;
        }

        return $this->evaluateDynamicContent($statements);
    }
Renders dynamic content returned by the given PHP statements.
This method is mainly used together with content caching (fragment caching and page caching)
when some portions of the content (called *dynamic content*) should not be cached.
The dynamic content must be returned by some PHP statements.
@param string $statements the PHP statements for generating the dynamic content.
@return string the placeholder of the dynamic content, or the dynamic content if there is no
active content cache currently.