C# と VB.NET の質問掲示板

■No102045 (くま さん) に返信

> またはこちら
>     windowObjectReference = window.open('', windowName);
> 	let elem = windowObjectReference.document.createElement('a');
> 	elem.href = url;
> 	elem.rel = "noreferrer";
> 	windowObjectReference.document.body.appendChild(elem);
> 	elem.click();
> 

なるほど、それで複数 a タグをクリックしても同じ window で表示されて要求ヘッダに Refer
は含まれなくなりますね。

それを MDN の記事、

Window.open()
https://developer.mozilla.org/ja/docs/Web/API/Window/open

の「既存のウィンドウを再利用して target="_blank" を防止する」のセクションにある
サンプルコードに組み込んで、同じ a タグを続けてクリックしても要求が出ないように
するのが良さそうです。

＜!DOCTYPE html＞

＜html xmlns="http://www.w3.org/1999/xhtml"＞
＜head runat="server"＞
    ＜meta http-equiv="Content-Type" content="text/html; charset=utf-8" /＞
    ＜title＞＜/title＞
    ＜script type="text/javascript"＞
        let windowObjectReference = null; // global variable
        let previousURL; /* global variable that will store the
                    url currently in the secondary window */

        function openRequestedSingleTab(url) {
            if (windowObjectReference === null || windowObjectReference.closed) {
                let a = document.createElement("a");
                a.href = url;
                a.rel = "noreferrer";
                windowObjectReference = window.open('', 'SingleSecondaryWindowName');
                windowObjectReference.document.body.appendChild(a);
                a.click();
            } else if (previousURL !== url) {
                let a = document.createElement("a");
                a.href = url;
                a.rel = "noreferrer";
                windowObjectReference = window.open('', 'SingleSecondaryWindowName');
                windowObjectReference.document.body.appendChild(a);
                a.click();
                /* if the resource to load is different,
                   then we load it in the already opened secondary window and then
                   we bring such window back on top/in front of its parent window. */
                windowObjectReference.focus();
            } else {
                windowObjectReference.focus();
            }
            previousURL = url;
            /* explanation: we store the current url in order to compare url
               in the event of another call of this function. */
        }

        window.addEventListener('DOMContentLoaded', () =＞ {
            const links = document.querySelectorAll("a[target='SingleSecondaryWindowName']");

            for (const link of links) {
                link.addEventListener(
                    "click",
                    (event) =＞ {
                        openRequestedSingleTab(link.href);
                        event.preventDefault();
                    },
                    false
                );
            }
        });
    ＜/script＞
＜/head＞
＜body＞
    ＜a href="default" target="SingleSecondaryWindowName" rel="noreferrer"＞Default＜/a＞
    ＜br /＞
    ＜a href="about" target="SingleSecondaryWindowName" rel="noreferrer"＞About＜/a＞
    ＜br /＞
    ＜a href="contact" target="SingleSecondaryWindowName" rel="noreferrer"＞Contact＜/a＞
＜/body＞
＜/html＞