Swift：WKwebview使用for循环解析多个网站？

Question

所以我的项目背后的想法是这样的。我有一个文本框，用户将键入并添加到“类代码”列表中。然后，我将在这些类代码上使用for循环，并在该迭代中使用该类代码解析特定网站。

在每次迭代中，我想做一些HTML解析来废弃数据，但每次我打印出该网站的HTML时，它都是一个空的html文档。

我非常感谢有关如何在for循环的每次迭代中解析html网站的一些帮助

import UIKit
import WebKit
class ViewController: UIViewController {
    
    @IBOutlet weak var classCode: UITextField!
    
    
    var webview = WKWebView()
    var classCodes: Array<String> = Array()
    var sections: Array<Int> = Array()
    
    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
    }
    
    @IBAction func add() {
        classCodes.append(classCode.text!)
        loadURL(code: classCode.text!)
        classCode.text = nil
        //might have to check if what they added was a valid course code, or else the parser might be trying to parse an invalid code
        
    }
    
    
    
    @IBAction func createTapped() {
        
        for code in classCodes {
        let url = URL(string:    "https://app.testudo.umd.edu/soc/search?courseId=\(code)&sectionId=&termId=201801&openSectionsOnly=true&_openSectionsOnly=on&creditCompare=&credits=&courseLevelFilter=ALL&instructor=&_facetoface=on&_blended=on&_online=on&courseStartCompare=&courseSartHour=&courseStartMin=&courseStartAM=&courseEndHour=&courseEndMin=&courseEndAM=&teachingCenter=ALL&_classDay1=on&_classDay2=on&_classDay3=on&_classDay4=on&_classDay5=on")!
            
            let request = URLRequest(url: url)
            webview.load(request)
            webview.evaluateJavaScript("document.documentElement.outerHTML.toString()", completionHandler: { (value, error) in
                print(value)
                
            })
        }