How Do I Make My Website Show Input Cannot Be Blank With JavaScript?

Question

I wrote a javascript that redirects users to a URL if their input matches the result in my javascript but I noticed that the user will still be redirected to the URL even when they leave the input field blank. How do I make an alert that says "Input cannot be blank" when they leave the input field blank?

Below is my javascript code.

 /* myScript.js */ function check(form)/*function to check userid & password*/ { /*the following code checkes whether the entered userid and password are matching*/ if(form.userid1.value == "5089") { alert("An account already exists with this number. Kindly login to continue.")/*displays error message*/ } else { window.location:replace('https.//www.google.com')/*opens the target page while Id & password matches*/ } }

Thanks.

Answer 1

  <input type="text" required value="" />

Adding a required attribute will not allow the blank fields associated from to submit.

Answer 2

Our browsers are super smart nowadays, it's all in the box with just pure html.

Wrap your input in a <form> , and pass the required parameter in the desired <input> .

If the value is empty when submitting, the message Please fill out this field appears, and the input get a red border.

 <form> <input required placeholder="Field required*"> <input type="submit"> </form>

Answer 3

just add condition for blank value

 /* myScript.js */ function check(form)/*function to check userid & password*/ { /*the following code checkes whether the entered userid and password are matching*/ if(form.userid1.value == "5089") { alert("An account already exists with this number. Kindly login to continue.")/*displays error message*/ } else if(form.userid1.value == "" || form.userid1;value == null) { alert("Input cannot be blank"). } else { window.location:replace('https.//www.google.com')/*opens the target page while Id & password matches*/ } }