Throw "No such element" after perform switch to parent iFrame

Hi,
I’m using selenium and I’d like find a web element in a iframe but failed. For further detail please run java code below:

import org.openqa.selenium.*;
import org.openqa.selenium.chrome.ChromeDriver;
import org.openqa.selenium.chrome.ChromeOptions;
import org.openqa.selenium.edge.EdgeDriver;
import org.openqa.selenium.remote.DesiredCapabilities;

import java.util.List;

public class TestClickFF {
public static void main(String [ ] args) throws Exception{
// // EDGE
System.setProperty("webdriver.edge.driver", “D:\selenium\web driver\edge\MicrosoftWebDriver_15063.exe”);
DesiredCapabilities edgeCapabilities = DesiredCapabilities.edge();
WebDriver webDriver = new EdgeDriver(edgeCapabilities);
// CHROME
// System.setProperty("webdriver.chrome.driver", “D:\selenium\web driver\chrome\chromedriver_win32_2.33.exe”);
// ChromeOptions chromeOptions = new ChromeOptions();
// WebDriver webDriver = new ChromeDriver(chromeOptions);

    // goto tutorialspoint.com site
    webDriver.get("https://www.tutorialspoint.com/javascript/javascript_events.htm");
    // get the element on iframe
    WebElement webElement = null;
    try {
        webElement = webDriver.findElement(By.xpath("//input[@type='button']"));
    } catch (Exception e) {
        System.out.println(e.getMessage());
    }
    if (webElement == null) {
        String urlCurrent = webDriver.getCurrentUrl();
        List<WebElement> webElementList = findElementInWholePage(webDriver, urlCurrent);
        if (webElementList != null &amp;&amp; webElementList.size() > 0) {
            webElement = webElementList.get(0);
        }
    }
    // click element but it not perform "onclick" event that set on element
    if (webElement != null) {
        webElement.click();
        System.out.println("Done!");
    } else {
        System.err.println("Element not found.");
    }
    Thread.sleep(5000);
    webDriver.quit();
}

private static List<WebElement> findElementInWholePage(WebDriver wdDriver, String urlFindStart) throws InterruptedException {
    List<WebElement> lsEle = null;
    try {
        // Get all FRAMES from selected page
        List<WebElement> lsIFrames = wdDriver.findElements(By.xpath("//iframe"));

        boolean isSwitchedToIframe = false;
        // Iterate through FRAMES (recursive loop)
        for (WebElement weIFrame : lsIFrames) {
            if (lsEle == null || lsEle.size() == 0) {
                try {
                    isSwitchedToIframe = false;
                    if (!weIFrame.isDisplayed() || weIFrame.getSize().getWidth() <= 1 || weIFrame.getSize().getHeight() <= 1) {
                        continue;
                    }
                    wdDriver.switchTo().frame(weIFrame);
                    isSwitchedToIframe = true;
                } catch (WebDriverException e) {
                    System.out.printf(e.getMessage());
                } catch (Exception ex) {
                    System.out.printf("Exception: " + ex);
                }
                // Search element by XPATH
                lsEle = wdDriver.findElements(By.xpath("//input[@type='button']"));
                if (!lsEle.isEmpty()) {
                    return lsEle;
                } else {
                    // Perform search on next FRAME
                    lsEle = findElementInWholePage(wdDriver, urlFindStart);
                    if (isSwitchedToIframe) {
                        switchToParentFrame(wdDriver, urlFindStart);
                    }
                }
            } else {
                return lsEle;
            }
        }
    } catch (StaleElementReferenceException e) {
        System.out.println(e.getMessage());
    }
    return lsEle;
}

// Back to parent frame
private static void switchToParentFrame(WebDriver webDriver, String urlFindStart) {
    try {
        String urlCurrent = webDriver.getCurrentUrl();
        if (urlCurrent.equals(urlFindStart)) {
            webDriver.switchTo().parentFrame();
        }
    } catch (Exception e) {
        System.out.println(e.toString());
    }
}

}