CODEWITHSUNDEEP
javascripthtml
SkyjumperTalon
SkyjumperTalon

Reputation: 101

How to make an alert when a form item is not answered?

I'm very new to JS. But basically, I'm creating a form. Using JavaScript, how do I take a form so that you must fill in form data?

Thanks!

HTML:

<form>
            <p>First Name:</p>
            <input type="text" name="firstname" class="form">
            <p>Last Name:</p>
            <input type="text" name="lastname" class="form">
            <p>Email:</p>
            <input type="text" name="email" class="form">
            <p>Questions / Concerns:</p>
            <textarea name="concerns" rows="5" cols="30"></textarea>
            <br>
            <input type="submit" name="submit" value="Submit">
            <input type="reset" name="reset" value="Reset">
        </form>

Upvotes: 0

Views: 235

Answers (2)

Osama
Osama

Reputation: 3040

use document.getElementByTagName to get the input tag Use addEventListner with first parameter as blur to detect input leave Use this.value within if statement to check if empty Alert something 

var element=document.getElementByTagName(input);
element.addEventListner("blur",myFunction);
function myFunction(){
if(this.value==''){
alert ("write something");
}
}

Upvotes: 1

Ashutosh
Ashutosh

Reputation: 1050

There are multiple ways of solving this particular problem.

The easiest way would be to use the required tag in elements:

<input type="text" name="firstname" class="form" required>

Edit: This may not work in very old browsers.But I don't believe you need to worry about that now.

Use required tag in all of your input elements which you need filling compulsorily.

Once you have your basic problem solved, look at using javascript functions for validation. Ref: https://www.w3schools.com/js/js_validation.asp

Once you know this, you can safely progress to reading on how validation is done on large projects- https://validatejs.org/

Upvotes: 3

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