如何在執行捕獲之前等待網頁加載？

某些網頁可能需要一段時間才能加載或包含您想要的特定內容 int預計可能會在主頁加載後加載。在內容通過 JavaScript 加載的 AJAX 密集型網頁上尤其如此。

GrabzIt 檢測網頁何時加載，但對於上面列出的某些特定情況，它需要一些額外的指令，這些指令應在捕獲之前使用，或者在捕獲之前等待指定的 HTML 元素出現。先。如果您要截取網頁屏幕截圖或轉換 HTML，則可以使用這些技術 into PDF、圖像或 Word 文檔，您將獲得高級套餐。然而，這兩種技術的最長等待時間都限制為三十秒。

最好不要使用太大的延遲，因為在捕獲排隊的異常情況下，大的延遲會降低捕獲優先級，儘管有一些巧妙的解決方法對此。

這些功能也可以在我們的網上截圖及刮板機的工具。

如何在執行捕獲之前等待指定時間？

只需指定以毫秒為單位的延遲，這就是捕獲將等待的時間。請記住，一秒有 1000 毫秒。以下所有示例在捕獲網頁之前都會等待三秒鐘。

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GrabzItClient grabzIt = new GrabzItClient("Sign in to view your Application Key", "Sign in to view your Application Secret");
ImageOptions options = new ImageOptions();
options.Delay = 3000;
grabzIt.URLToImage("http://www.spacex.com", options);
grabzIt.SaveTo("images/result.jpg");

GrabzItClient grabzIt = new GrabzItClient("Sign in to view your Application Key", "Sign in to view your Application Secret");
ImageOptions options = new ImageOptions();
options.setDelay(3000);
grabzIt.URLToImage("http://www.spacex.com", options);
grabzIt.SaveTo("images/result.jpg");

<script src="https://cdn.jsdelivr.net/npm/@grabzit/js@3.5.2/grabzit.min.js"></script>
<script>
GrabzIt("Sign in to view your Application Key").ConvertURL("http://www.spacex.com", 
{"delay": 3000}).Create();
</script>

var grabzit = require('grabzit');

var client = new grabzit("Sign in to view your Application Key", "Sign in to view your Application Secret");
var options = {"delay":"3000"};
client.url_to_image("http://www.spacex.com", options);
client.save_to("images/result.jpg", function (error, id){
    if (error != null){
        throw error;
    }
});

$grabzIt = GrabzItClient->new("Sign in to view your Application Key", "Sign in to view your Application Secret");
$options = GrabzItImageOptions->new();
$options->delay(3000);
$grabzIt->URLToImage("http://www.spacex.com", $options);
$grabzIt->SaveTo("images/result.jpg");

$grabzIt = new \GrabzIt\GrabzItClient("Sign in to view your Application Key", "Sign in to view your Application Secret");
$options = new \GrabzIt\GrabzItImageOptions();
$options->setDelay(3000);
$grabzIt->URLToImage("http://www.spacex.com", $options);
$grabzIt->SaveTo($filepath);

grabzIt = GrabzItClient.GrabzItClient("Sign in to view your Application Key", "Sign in to view your Application Secret")
options = GrabzItImageOptions.GrabzItImageOptions()
options.delay = 3000
grabzIt.URLToImage("http://www.spacex.com", options)
grabzIt.SaveTo("images/result.jpg")

https://api.grabz.it/services/convert?key=Sign in to view your Application Key&format=jpg&delay=3000&url=https%3A%2F%2Fspacex.com%2F

grabzIt = GrabzIt::Client.new("Sign in to view your Application Key", "Sign in to view your Application Secret")
options = GrabzIt::ImageOptions.new()
options.delay = 3000
grabzItClient.url_to_image("http://www.spacex.com", options)
grabzItClient.save_to("images/result.jpg")

如何在執行捕獲之前等待 HTML 元素出現？

此技術對於使用 AJAX 方法加載內容的網頁特別有用。首先使用瀏覽器的開發工具來識別需要等待出現的元素，記下其 id、類或製作更複雜的 CSS 選擇器。然後指定這個 CSS選擇器一旦元素變得可見，網頁就會被捕獲。請注意，如果有多個匹配的 HTML 元素，只要有一個元素可見，它就會立即出現。

ASP.NET
Java的
JavaScript的
Node.js的
Perl的
PHP
蟒蛇
REST API
紅寶石

GrabzItClient grabzIt = new GrabzItClient("Sign in to view your Application Key", "Sign in to view your Application Secret");
ImageOptions options = new ImageOptions();
options.WaitForElement = "#Content";
grabzIt.URLToImage("http://www.spacex.com", options);
grabzIt.SaveTo("images/result.jpg");

GrabzItClient grabzIt = new GrabzItClient("Sign in to view your Application Key", "Sign in to view your Application Secret");
ImageOptions options = new ImageOptions();
options.setWaitForElement("#Content");
grabzIt.URLToImage("http://www.spacex.com", options);
grabzIt.SaveTo("images/result.jpg");

<script src="https://cdn.jsdelivr.net/npm/@grabzit/js@3.5.2/grabzit.min.js"></script>
<script>
GrabzIt("Sign in to view your Application Key").ConvertURL("http://www.spacex.com", 
{"waitfor": "#Content"}).Create();
</script>

var grabzit = require('grabzit');

var client = new grabzit("Sign in to view your Application Key", "Sign in to view your Application Secret");
var options = {"waitForElement":"#Content"};
client.url_to_image("http://www.spacex.com", options);
client.save_to("images/result.jpg", function (error, id){
    if (error != null){
        throw error;
    }
});

$grabzIt = GrabzItClient->new("Sign in to view your Application Key", "Sign in to view your Application Secret");
$options = GrabzItImageOptions->new();
$options->waitForElement("#Content");
$grabzIt->URLToImage("http://www.spacex.com", $options);
$grabzIt->SaveTo("images/result.jpg");

$grabzIt = new \GrabzIt\GrabzItClient("Sign in to view your Application Key", "Sign in to view your Application Secret");
$options = new \GrabzIt\GrabzItImageOptions();
$options->setWaitForElement("#Content");
$grabzIt->URLToImage("http://www.spacex.com", $options);
$grabzIt->SaveTo($filepath);

grabzIt = GrabzItClient.GrabzItClient("Sign in to view your Application Key", "Sign in to view your Application Secret")
options = GrabzItImageOptions.GrabzItImageOptions()
options.waitForElement = "#Content"
grabzIt.URLToImage("http://www.spacex.com", options)
grabzIt.SaveTo("images/result.jpg")

https://api.grabz.it/services/convert?key=Sign in to view your Application Key&format=jpg&waitfor=%23Content&url=https%3A%2F%2Fspacex.com%2F

grabzIt = GrabzIt::Client.new("Sign in to view your Application Key", "Sign in to view your Application Secret")
options = GrabzIt::ImageOptions.new()
options.waitForElement = "#Content"
grabzItClient.url_to_image("http://www.spacex.com", options)
grabzItClient.save_to("images/result.jpg")

該技術可以與首先提到的延遲方法結合使用。允許您等待 HTML 元素出現，然後在創建捕獲之前再等待一段時間。

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