Although it discussed here: AngularJS with Sharepoint 2010 not working And uses of timeout in order to make the page being loaded synchronous (I don't like this solution) - it's not work.
I have loaded the html of the webpart page after the angular is loaded:
window.onload = function(){
setTimeout(function(){
str+='<p>Name : <input type="text" ng-model="name" placeholder="Enter
name here"></p>'
str+='<h1>Hello {{name}}</h1>'
str+='<button id="submit"></button>'
document.getElementById("ngApp").innerHTML=str;
}, 2500);
}
The output is: "Hello {{name}}"
<script src=".../angularjs.js"></script>
<script src=".../code.js"></script>