How to use value of dropdown on spreadsheet to determine what app script runs?

I have a drop down on my spreadsheet with two options. How can I have script editor read the drop down cell and then provide a specific operation based on what's selected in the drop down. I tried the following below, which always produces the second window no matter what's selected in the drop down... Am I going at this all wrong? Or is my code below just flawed?

function onOpen(){

var sheet = SpreadsheetApp.getActiveSpreadsheet();
var menu = sheet.getSheetByName('1__Menu');
var dropDown = menu.getRange(1,3);

if (dropDown = 'Edit/View Rider'){
//Set up Window
var appEdit = UiApp.createApplication().setTitle('Edit Rider');
var panelEdit = appEdit.createVerticalPanel();
var labelE = appEdit.createLabel('Yippee!');
panelEdit.add(labelE);  
appEdit.add(panelEdit);
var doc = SpreadsheetApp.getActive();
doc.show(appA);
}  

if (dropDown = 'Delete Rider'){
//Set up Window
var appDelete = UiApp.createApplication().setTitle('Delete Rider');
var panelDelete = appDelete.createVerticalPanel();
var labelD = appDelete.createLabel('Well Done!');
panelDelete.add(labelD);  
appDelete.add(panelDelete);
var doc = SpreadsheetApp.getActive();
doc.show(appDelete);
}