Questions And Answers

More Tutorials

Check if TextBox Is Empty in Javascript

raise an alert message if the textbox is left empty

function a(id)
    var n=document.getElementById(id).value;
    if (n.length < 1)
        window.alert("Field is blank");
        return false;

onchange will work only if the value of the textbox changed compared to the value it had before, so for the first time it won't work because the state didn't change.

So it is better to use onblur event or on submitting the form.

function checkTextField(field) {
  document.getElementById("error").innerText =
    (field.value === "") ? "Field is empty." : "Field is filled.";

<input type="text" onblur="checkTextField(this);" />
<p id="error"></p>


In this page (written and validated by ) you learned about . What's Next? If you are interested in completing Javascript tutorial, we encourage you simply to start here: Javascript Tutorial.

Incorrect info or code snippet? We take very seriously the accuracy of the information provided on our website. We also make sure to test all snippets and examples provided for each section. If you find any incorrect information, please send us an email about the issue:

Share On:

Mockstacks was launched to help beginners learn programming languages; the site is optimized with no Ads as, Ads might slow down the performance. We also don't track any personal information; we also don't collect any kind of data unless the user provided us a corrected information. Almost all examples have been tested. Tutorials, references, and examples are constantly reviewed to avoid errors, but we cannot warrant full correctness of all content. By using, you agree to have read and accepted our terms of use, cookies and privacy policy.