php 语法

function showImage($url, $width='', $height='')
{
    if(empty($url))
        return ;
    $url = C('IMG_URL').$url;
    if($width)
        $width = "width='$width'";
    if($height)
        $height = "height='$height'";
    echo "<img src='$url' $width $height />";
}