如果前台没有传输当前请求的宽度和高度，我们有时候需要用php借助javascript获取屏幕的宽和高，以控制现实的样式，代码如下：

<?php
if (isset($_GET['width']) AND isset($_GET['height'])) {
    // output the geometry variables
    echo "Screen width is: " . $_GET['width'] . "<br />\n";
    echo "Screen height is: " . $_GET['height'] . "<br />\n";
} else {
    // pass the geometry variables
    // (preserve the original query string
    //   -- post variables will need to handled differently)

    echo "<script language='javascript'>\n";
    echo "  location.href=\"${_SERVER['SCRIPT_NAME']}?${_SERVER['QUERY_STRING']}"
        . "&width=\" + screen.width + \"&height=\" + screen.height;\n";
    echo "</script>\n";
    exit();
}