Automating Oauth2 token retrieval- 'Implicit Grant' method . Java script in auth manager failing

[ManRam2020]

We are trying to automate the OAuth2 Azure token retrieval and we use Implicit grant method. 

In the java script to automate the login UI page , we dont have id's , had to use the Xpath, so replaced the ids with xpaths, used the findchildbyXpath method, a compilation error is thrown saying FindbychildXpath is not available, so tried importing the package, when done, it throws script missing ; error. It is not liking any import statements there. So, not sure what is missing. Could someone please throw some ideas ? I am following the documentation in SmartBear -

https://support.smartbear.com/readyapi/docs/requests/auth/types/oauth2/automate/sample.html

Also, followed the recommendations in the community discussion, 
https://community.smartbear.com/t5/SoapUI-Pro/how-to-automate-our-manual-Oauth2-0-process/td-p/18348...

This is the javascript i am using, 

import javax.xml.xpath.XPathExpression ;

// This function asks for permission to use OAuth. The user must be logged in to use it. Logging in is performed in the script below.
function consent() {
if (document.FindChildByXpath('//*[@id="i0281"]/div/div/div[1]/div[3]/div/div/div')){
document.FindChildByXpath('//*[@id="i0281"]/div/div/div[1]/div[3]/div/div/div').click();
}
}

// This function fills user password in when the user name is already known. It uses the project-level "pass" property.
function fillpwd() {
document.FindChildByXpath('//*[@id="i0281"]/div/div/div[1]/div[3]/div/div[2]').value = 'xxxxxxx';
document.FindChildByXpath('//*[@id="idSIButton9"]').Click();
window.setInterval(consent, 100);
}

//Thread.Sleep(3000);
// This script checks what page is displayed and provides the appropriate data. It uses the project-level "user" and "pass" properties.
if (document.FindChildByXpath('//*[@id="i0281"]/div/div/div[1]/div[3]/div/div/div') && document.getElementByXpath('//*[@id="loginHeader"]/div')) {
document.FindChildByXpath('//*[@id="tilesHolder"]/div[1]/div/div').value = 'xxxxxx';
document.FindChildByXpath('//*[@id="tilesHolder"]/div[1]/div/div/div/div[3]/div').click();
window.setTimeout(fillpwd, 100);
//Thread.Sleep(3500);
} else if (document.FindChildByXpath('//*[@id="i0281"]/div/div/div[1]/div[3]/div/div[2]')) {
// Thread.Sleep(3500);
fillpwd();
} else if(document.FindChildByXpath('//*[@id="i0281"]/div/div/div[1]/div[3]/div/div/div')){
window.setInterval(consent, 100);
}

[NBorovykh · Accepted solution]

Hi @ManRam2020,

The document object does not have the FindChildByXpath() method, and it cannot be added to it anyhow. 

Please try using the evaluate() method instead: https://developer.mozilla.org/en-US/docs/Web/API/Document/evaluate

[ManRam2020]

Thank you so much for the response on this , Natalie, i tried using  evaluate() method per your recommendation, it throws errors saying two arguments needs to be passed.

TypeError: Failed to execute 'evaluate' on 'Document': 2 arguments required, but only 1 present.Uncaught TypeError: Failed to execute 'evaluate' on 'Document': 2 arguments required, but only 1 present.Uncaught TypeError: Failed to execute 'evaluate' on 'Document': 2 arguments required, but only 1 present.Uncaught

Also, our UI is defaulted to go through IE, in the link shared, it says, evaluate method is not supported for IE.

Am i missing something ? I am pretty new to API automation. 

Thanks in advance.