How to validate forms in Angular JS - angularjs

Question

i'm a newbie in angular JS. and i was trying the input type="text", i'm retrieving my name from my controller and i was using $dirty and $invalid to validate my data but it isn't showing when i make the input field empty.
JS Fiddle : https://jsfiddle.net/U3pVM/24718/
var FormValidations = angular.module('FormValidations',[]);
FormValidations.controller('FormsValidations', function( $scope ){
$scope.formsToBeValidated = {
firstName : 'Daniel'
};
});

Answer 1

Unless you add name attribute to form level field, that will not get included in form object when you specified in the name attribute on form, currentlyh it is name="studentForm". Do add name="firstName" to your input field
<input type="text" class="form-control"
name="firstName" ng-model="formsToBeValidated.firstName" required/>
Forked Fiddle
For more information you could refer this answer, which has more detailed
More convenient way to solve this issue would be using ng-messages instead of using ng-show/ng-hide, for that you have to include ng-messages module with its ng-messages dependency.

Answer 2

you should try this:
<input name="firstName" type="text" class="form-control"
ng-model="formsToBeValidated.firstName" required>
fiddle

Answer 3

as other says , add "name" attribute to your input.
I made a custom directive to display error on input using ng-message ( so you have to include it )
directives.directive('inputerrormsg', function () {
return {
replace: true,
restrict: 'E',
plain: true,
scope: {
inputdata: "=",
dpattern: '#'
},
template: '<div class="help-block has-error text-center" ng-messages="inputdata[\'$error\']" >' +
'<p ng-message="required">{{\'The field is required\'| translate }}</p>' +
'<p ng-message="minlength">{{\'Input too short\'| translate }}</p>' +
'<p ng-message="maxlength">{{\'Input too long\'| translate }}</p>' +
'<p ng-message="email">{{\'Email invalid\'| translate }}</p>' +
'<p ng-message="date">{{\'Date invalid\'| translate }}</p>' +
'<p ng-message="number">{{\'Write number only\'| translate }}</p>' +
'<p ng-message="pattern">' +
'<span ng-switch="dpattern">' +
'<span ng-switch-when="date">{{\'Date incorrecte: YYYY, YYYY/MM, YYYY/MM/DD\' |translate}}</span>' +
'<span ng-switch-default>{{\'Saisir uniquement des lettres\'| translate }}</span>' +
'</span>' +
'</p>' +
'</div>'
}
});
USAGE :
required field
<div style="padding-left: 0px;" ng-class="{ 'has-error' : !formDeter.scientificname.$valid">
<div class="input-group no-padding">
<input type="text"
class="form-control input-md" name="scientificname"
required />
<span class="input-group-addon">
<span class="glyphicon glyphicon-question-sign"></span>
</span>
</div>
<dir.inputerrormsg inputdata="formDeter.scientificname" ></dir.inputerrormsg>
EMail :
<div class="form-group row" ng-class="{ 'has-error' : !formData.email.$valid }">
<label class="col-xs-4 control-label">{{"Email" | translate }}</label>
<div class="col-xs-8 input-group">
<input type="email" class="form-control input-md" ng-model="email" name="email" id="email" required
placeholder="{{'Email' | translate }}"/>
</div>
<dir.inputerrormsg inputdata="formData.email" dpattern="email" ></dir.inputerrormsg>
</div>
Number only :
<div class="form-group row" ng-class="{ 'has-error' : !formLocalisation.decimallongitude.$valid }">
<label class="col-xs-4 control-label">{{"Longitude" | translate }}</label>
<div class="col-xs-8 input-group">
<input type="number" popover-trigger="focus" placeholder="{{'Longitude' | translate }}"
class="form-control input-md"
ng-model="specimen.decimallongitude" name="decimallongitude"
/>
<span class="input-group-addon" >
<span class="glyphicon glyphicon-question-sign"></span>
</span>
</div>
<dir.inputerrormsg inputdata="formLocalisation.decimallongitude" ></dir.inputerrormsg>
</div>
...

Answer 4

You didn't specified name to your input. Try this:
<form name="studentForm" novalidate>
<input type="text" class="form-control" name ="input" ng-model="formsToBeValidated.firstName" required>
<span studentForm.input.$error.required && studentForm.input.$dirty>First Name is Required</span>
</form>