ios - Swift WKWebView and Javascript Interaction -

i've been having trouble getting wkwebview in swift trigger javascript in loaded web page. im trying use javascript change background color on website if user swipes left, swipes right, or clicks button. appreciated.

import uikit import webkit  class myviewcontroller: uiviewcontroller, wknavigationdelegate {  @iboutlet var container: uiview! var webview: wkwebview?  override func viewdidload() {     super.viewdidload()      self.webview = wkwebview()     container.addsubview(webview!)      webview?.allowsbackforwardnavigationgestures = true     webview?.navigationdelegate = self      let leftswipe = uiswipegesturerecognizer(target: self, action: #selector(myviewcontroller.handleswipes(_:)))     let rightswipe = uiswipegesturerecognizer(target: self, action: #selector(myviewcontroller.handleswipes(_:)))     leftswipe.direction = .left     rightswipe.direction = .right      view.addgesturerecognizer(leftswipe)     view.addgesturerecognizer(rightswipe) }  override func viewdidappear(animated: bool) {      let frame = cgrectmake(0, 0, container.bounds.width, container.bounds.height)     webview!.frame = frame      let url = nsurl(string: "https://www.google.com")     let request = nsurlrequest(url: url!)     self.webview!.loadrequest(request)  }   @ibaction func buttonclick(sender: anyobject) {       webview?.evaluatejavascript("document.getelementbyid('hplogo').style.backgroundcolor='red';", completionhandler: nil)  }     func handleswipes(sender:uiswipegesturerecognizer){      if (sender.direction == .left){        webview?.evaluatejavascript("document.getelementbyid('hplogo').style.backgroundcolor='black';", completionhandler: nil)      }      if (sender.direction == .right){           webview?.evaluatejavascript("document.getelementbyid('hplogo').style.backgroundcolor='green';", completionhandler: nil)      }  }  func webview(webview: wkwebview, didfinishnavigation navigation: wknavigation!) {   webview?.evaluatejavascript("document.getelementbyid('hplogo').style.backgroundcolor='red';", completionhandler: nil) }  } 

you misspelled javascript's function name. should getelementbyid instead of getelementbyid:

document.getelementbyid('hplogo').style.backgroundcolor = '...'