I have just started working with applescript and am trying web automation. My task is to launch the browser, sign in and then click on certain links. 

While my script is able to launch browser and sign in, I am not able to automate the mouse click on links or buttons. I have tried a number of solutions available on the web(including those on stackoverflow) but nothing seems to work. The error message I am getting is 'value missing'

Since I am a completely new at applescript, I am not completely sure whether this can be done or not. Have a look at my script:
(The comments "(*or:  *)" are the alternates I have tried).

    set userID to "username"
    set pwd to "password"

    tell application "Safari"
    activate

    make new document with properties {URL:"http://example.com"}  (*or:         
    open location "example.com"*)

    tell application "System Events"
    delay 4
    keystroke tab

    keystroke userID
    delay 1
    keystroke tab

    keystroke pwd
    delay 1
    keystroke return
    delay 3

    tell application "Safari"  
   (*or: tell application "Safari" to tell active tab of window 1*)

    do JavaScript "$( 'apps-button .switcher-button switcher-button-   
    left :equ(0)').click()" in front document
    (*or: do JavaScript "document.getElementByID('apps-  
     button').click()"*)

    end tell
    end tell
    end tell



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Using: android.opengl.GLES20.glGetString(android.opengl.GLES20.GL_RENDERER) I get Bluestacks.