Assign random ngModel to directive - angularjs

Question

I'm trying to assign a random string to ngModel. But I can't even seem to assign a regular string to it. In the code below, I'm trying to change the ngModel to "new", but in chrome, it's still showing me that the ngModel is "placeholder". What am I doing wrong?
app.directive("page", function(){
return {
restrict: 'E',
replace: true,
template: '<div ng-model="placeholder"></div>',
controller: function ($scope, $element) {
$scope.placeholder = "new";
}
}});
The plain div tag was just an example. What I actually have is a content editable div that I've bound to a textarea with a contenteditable directive. I made a button to allow me to add as many of these directives as I want, but when I add this directive, I'd like a new ng-model for each one, because that's what I'm using to save the content of each content editable div to a file.
This is the full example in case it might help someone else. I put the addPage directive to a button, which, when clicked, appends a new content editable div (which I'm calling a page). There is one more directive that I didn't include (contenteditable) because I got it from the bottom of the docs over here
app.directive("addPage", function($compile){
return function(scope, element, attrs){
element.bind("click", function(){ angular.element(document.getElementById('container')).append($compile('<page></page>')(scope));
});
};
});
app.directive("page", function(){
return {
restrict: 'E',
replace: true,
// template: '<div class="page" contenteditable strip-br="true" ng-model="chapter"></div>',
template: function (elem, attr) {
var test="chapter.two"; //in reality, I will generate a random string to keep these divs unique
return '<div class="page" contenteditable strip-br="true" ng-model=' + test +'></div>'
}
}});
In my controller, I have this object that is used to store all the ng-model content
$scope.chapter = {};

Answer 1

I think you are approaching this a bit backwards. Starting with the model, you'd need an array to keep the values from all of the inputs / contenteditables.
.controller("MainCtrl", function($scope){
$scope.data = [{v: ""}]; // first element
$scope.addContentEditable = function(){
$scope.data.push({v: ""});
};
})
Then, you can bind to each element of that array easily, and add elements at will:
<button ng-click="addContentEditable()">Add</button>
<div ng-repeat="item in data" ng-model="item.v" contenteditable></div>
I'm not sure exactly how the page directive needs to be used here, but one way or another, the approach is the same as above.

Answer 2

If you just want to pass a string in you could use attributes and template(fn)
HTML
<div page="new">
Directive
app.directive("page", function () {
return {
restrict: 'E',
replace: true,
template: function (elem, attr) {
return '<div ng-model="' + attr.page + '"></div>';
}
}
});