javascript - Red textbox border color

I have a form with one textbox. I want to check when the textbox value is empty and make some sort of red border surrounding the textbox itself when it's empty.

if (document.getElementById('pageh').value == "") {
    alert("One of the fields is empty.");
    return false;
}

That's my validation, but how do I add the red border?

I have a form with one textbox. I want to check when the textbox value is empty and make some sort of red border surrounding the textbox itself when it's empty.

if (document.getElementById('pageh').value == "") {
    alert("One of the fields is empty.");
    return false;
}

That's my validation, but how do I add the red border?

Share Improve this question edited Dec 19, 2012 at 19:27 Sampson 269k76 gold badges545 silver badges568 bronze badges asked Dec 19, 2012 at 19:22 zarko 1511 gold badge3 silver badges11 bronze badges

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2 Answers 2

Sorted by: Reset to default 5

var field = document.getElementById('pageh');

if (field.value == "") {
    document.getElementById('pageh').style.border = "solid 1px red";
    alert("One of the fields is empty.");
    return false;
}

Maybe something like that?

var textbox = document.getElementById("pageh");
if (textbox.value.replace(/^\s+|\s+$/g, "") === "") {
    textbox.style.border = "1px solid #ff0000";
}

Note, don't be afraid of replace part: this is just cross-browser text trim.

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2 Answers 2