谢谢两位解答,然而还是报错:

PHP Warning – yii\base\ErrorException

Cannot use a scalar value as an array
1. in E:\www\yii2test\vendor\yiisoft\yii2\helpers\BaseHtml.php at line 261
 *
     * The rest of the options will be rendered as the attributes of the resulting script tag. The values will
     * be HTML-encoded using [[encode()]]. If a value is null, the corresponding attribute will not be rendered.
     * See [[renderTagAttributes()]] for details on how attributes are being rendered.
     * @return string the generated script tag
     * @see Url::to()
     */
    public static function jsFile($url, $options = [])
    {
        $options['src'] = Url::to($url);
        if (isset($options['condition'])) {
            $condition = $options['condition'];
            unset($options['condition']);
            return self::wrapIntoCondition(static::tag('script', '', $options), $condition);
        } else {
            return static::tag('script', '', $options);
        }
    }

使用Url::to()也是可以的。方法如下：

<?php
use yii\helpers\Url;
......
Url::to(['site/index']);