if typename question

Sorry if this is a silly question, but can anyone let me know why the if/else code below doesn't work?

The script is supposed to determine which out of two selected objects is a text frame and give it the variable 'text'

var docRef = app.activeDocument;
if (docRef.selection[0].typename = "TextFrame"){  var text = docRef.selection[0];  var other = docRef.selection[1];
} else {  var text = docRef.selection[1];  var other = docRef.selection[0];
};