Cannot disable submit button by $invalid while page load - angularjs

Question

I am trying to invalidate and disable the submit button on the load of the page, as not entering text into textbox is invalid, but my code is not working, can someone please provide the solution.
<div id="reg_bground">
<div id="formdiv" ng-app="myApp" ng-controller="valCtrl">
<form name="myForm" novalidate>
<div style="font-family:calibri; font-size:30px; font-weight:bolder;">
<span>Register:</span>
</div>
<div>
<span>Name:</span><br>
<input type="text" name="user" ng-model="user" required><br>
<p ng-show="myForm.user.$dirty && myForm.user.$invalid">*Please insert the name</p>
</div>
<input type="number">
<input type="submit" ng-disabled="myForm.user.$dirty && myForm.user.$invalid">
</form>
</div>
</div>

Answer 1

You essentially check for $dirty state in the submit button for disabled status.
<input type="submit" ng-disabled="myForm.user.$dirty && myForm.user.$invalid">
$dirty is only set to true when user has meddled with the myForm.user input, which is not the case on page load. Instead, try checking the $pristine state (or !$dirty)
<input type="submit" ng-disabled="myForm.user.$pristine || myForm.user.$invalid">

Answer 2

Delete the dirty check in the submit button:
<input type="submit" ng-disabled=" ̶m̶y̶F̶o̶r̶m̶.̶u̶s̶e̶r̶.̶$̶d̶i̶r̶t̶y̶ ̶&̶&̶ ̶ myForm.user.$invalid">

Answer 3

The field content is valid
$invalid working when you enter a input and input doesn't match your pattern .
you must use $error.required for your goal.
follwing will work
<div id="reg_bground">
<div id="formdiv" ng-app="myApp" ng-controller="valCtrl">
<form name="myForm" novalidate>
<div style="font-family:calibri; font-size:30px; font-
weight:bolder;">
<span>Register:</span>
</div>
<div>
<span>Name:</span><br>
<input type="text" name="user" ng-model="user" required><br>
<p ng-show="myForm.user.$dirty &&
myForm.user.$error.required">*Please insert the name</p>
</div>
<input type="number">
<input type="submit" ng-disabled="myForm.user.$dirty &&
myForm.user.$error.required">
</form>
</div>