The option will be selected if the expression inside the ng-selected attribute returns true. The ng-selected directive is necessary to be able to shift the value between true and false. In HTML, you cannot set the selected attribute to false the presence of the selected attribute makes the element selected, regardless of its value. If you want to report an error, or if you want to make a suggestion, do not hesitate to send us an e-mail:. Value Description expression An expression that will set the element's selected attribute if it returns true.
Powered by W3.In this article I will tell you how to compare two values using angular. We often create applications where we need to compare a few things just as in the case of entering a password and re-enter the password. In such a cases if the user is not providing the equal values then an error message needs to be shown.
AngularJS provides a feature for doing that easily, angular. As we already know, using AngularJS we can create dynamic things that can be changed according to the user requirements, so here I will create an application that can compare dynamic data. First of all you need to add an external Angular. After downloading the external file you need to add this file to the Head section of your application.
These initial values will be provided in the textboxes where the password needs to be entered and reentered. After this I have created a function "func ", this function will compare the values of these variables and will show an alert message accordingly. You can see that for comparing the values I have used angular. The first TextBox is bound to "firstPassword" and the second is bound to "secondPassword". This binding will provide the default values in these Textboxes.
After this a label is taken in which both the default passwords are bounded, this can be done using the ng-bind-template. On running the application you will see that some text is available in both of the textboxes in password format. Whatever is written in the Textboxes can be seen in the Label present after them. If I click on the button then a message will be shown that will show "false"; that's because the values were different:. Now I am changing the text in the second TextBox and making it similar to the first one you can check the Label.
After making the changes I clicked on the button and a True message is displayed as in the following:. View All. Compare Two Values Using angular. Anubhav Chaudhary Updated date, Feb 07 Introduction In this article I will tell you how to compare two values using angular. Step 1 First of all you need to add an external Angular.
Next Recommended Article. Getting Started With. NET 5. Getting Started with ML. NET Core.Hiding or showing parts of a DOM based on some conditions is a common requirement. This boolean value may come from a variable or a function. It is similar to the traditional switch, case statement. Download this demo example of ng-switch and ng-if.
Demo example of the ng-if is along with the ng-switch above. If you check all the framework, a success message come using the ng-if. It can fetch external HTML template depending on a specific condition. It can be used with a fixed part of page like header, footer.
Download the demo example of ng-include directive. View all posts by Gopal Juneja. In case you need the elements available but want to clean up after making the choice. I had this problem before when I was trying to swipe between 2 ui-views in my index.
I left both and removed the unnecessary element using. Bottom line — if you design your application right, you should be able to live without or well — minimal DOM Manipulation. I use it extensively and works like charm.
Now it even supports some level of expressions and conditions. You can use JQ more than just jqlite for sure as long as u r loading Jq before angular — as it uses it then instead of jqlite — but again it breaks the fun and design principle ….
I was trying to get my mob version view with a transition animation as native app. The only option was to have both views available and remove the unnecessary one after detection in the app.
Carla — supporting will be a real pain.
You will end up using IEShiv. You can do browser detection, and decide which animation to use. This is a good guide for the new angular animations ng 1. Skip to content Hiding or showing parts of a DOM based on some conditions is a common requirement. I guess the best option for the css3 detection would be modernizr. Can we open and close html tag conditionally? Is it possible?
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Want to level up your Angular skills? Who doesn't. Here's what you need to know. NgIf is a behavioral directive that allows us to toggle a template based on a conditional statement. The syntax for NgIf is nice and simple, we simply can declare it on an element, or component, and let it work its magic. Placing the ngIf directive on a component, or element, will in fact hide or show that element based on the expression you pass it to be evaluated.
This would then allow Angular to add a hidden attribute if the isLoggedIn property was true - we can show the nice message! If something is marked hidden, it is hidden from all presentations, including, for instance, screen readers. Read more on MDN about hidden. Learn about this over here in my next post.NgIf Directive - Angular 5 (Tutorial #10)
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NgIf & NgSwitch
Read the legal things. Here's what you need to know Show Me. Table of contents What is NgIf? Learn Angular the right way! Love the post?In this Tutorial let us look at the syntax of ngIf. We will show you how to use ngIf using example code. Angular 9. The ngIf is attached to a DOM element p element in the above example. It is then bound to an expression a condition in the above example. The expression is then evaluated by the ngIf directive. The expression must return either true or false.
If the expression evaluates to false then the entire element is removed from the DOM. If true then the element is inserted into the DOM. It removes the entire element along with its subtree from the DOM. It also removes the corresponding state freeing up the resources attached to the element. But just hides it. The second method with ngIf removes the element completely from the DOM. By using the Logical NOT! The better solution is to use the optional else block as shown in the next paragraph.
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The condition can be anything. It can be a property of the component class. It can be a method in the component class. The ngIf directive tries to coerce the value to Boolean. The ngIf allows us to define optional else block using the ng-template. Next, we have else clause bound to a template named elseBlock.
The template can be defined anywhere using the ng-template. Typically it is placed right after ngIf for readability. When the condition evaluates to false, then the ng-template with the name elseBlock is rendered by the ngIf Directive. You can also define then else block using the ng-template. When the condition is true, the template thenBlock is rendered. If false, then the template elseBlock is rendered. Create a boolean variable showMe in your app. The ngIf directive is attached to the div element.
The expression is evaluated and if it is truethen the div element is added to the DOM else it is removed from the DOM.Also, we will find out how the ngIf directive differs from using the "hidden" attribute. When we got the basics, we will move on to more advanced topics like using the "else"-condition with ng-template and logical operators.
Finally, we will take a look under the hood and see, how angular actually uses the ngIf directive. Also, this condition does also apply to all child elements of the element that has the ngIf directive:. That means, that it can be added to any tag in your template.
This includes regular HTML-tags like the "p"-tag shown above and even angular component selectors. At first sight, the angular ngIf directive seems to just the same thing as binding to the HTML5 "hidden" attribute.
So why do we need two ways to do the same thing? They are just invisible. Angulars' ngIf directive, on the other hand, is completely removing the selected part from the DOM. The great advantage of that is, that this method is not interfering with any CSS-Style-sheets at all. It is simply removing anything. Another very useful application of ngIf is when you need to check if a bound property is null before displaying some of its properties. For example, displaying a box with the users' information wouldn't make much sense if there is no information to display.
Normally this would result in an empty box to be shown. With the help of the ngIf directive, we can hide this box altogether, if the corresponding property is null or undefined anyway. The ngIf directive can be very handy to prevent "Cannot read property of undefined" errors, as well. Maybe we are using sub-properties of the bound property. For example the name of the user. Accessing this property if user is undefined will result in an error. But by checking the user-property for null before using its properties will prevent this.
This block is shown if the statement defined in the main block happens to be false. Notice, that the else block has to be an ng-template. The ng-template is a special element that is interpreted by angular and has no DOM counterpart. That means, that this tag is not included in the final HTML result, but only its content.
Compare Two Values Using angular.equals
We have to use ng-content, because a normal div would be picked up by the browser and be rendered all the time. Also, we have to give that block an ID notShow so we can reference it in our ngIf directive as the "else"-block. In some rare cases, it might be useful to have the ngIf directive from its actual result-block. This would enable us to swap the result of the block out on the fly, by just referencing another ng-template.