Is it possible to make an input="text" to require either an email or a tel?

Question

I made an <input type="text" placeholder="phone or email" required="required" /> and I was just wondering if I can make it so that it would require either a valid email or a number?

Answer 1

It is possible to implement HTML-only data validation on inputs using pattern attribute: http://jsfiddle.net/887saeeg/. Coupled with :valid and :invalid pseudo-classes, it is possible to have a decent error-checking functionality using only presentation technologies. Of course, a modern browser is required. (I cover browser-only validation in more detail in the last volume of my Functional CSS book series [available on Amazon]).

HTML:

<form>
    <input type = "text" placeholder = "Phone or Email" required pattern = "^([a-z0-9._%+-]+@[a-z0-9.-]+\.[a-z]{2,3})|(\d{3}-\d{3}-\d{4})$"/>
    <input type = "submit" value = "Send" />
</form>

EDIT: Example using CSS pseudo-classes: http://jsfiddle.net/292pp5gk/.

HTML:

<form>
    <label>
        <input type = "text" placeholder = "Phone or Email" required pattern = "^([a-z0-9._%+-]+@[a-z0-9.-]+\.[a-z]{2,3})|(\d{3}-\d{3}-\d{4})$"/>
        <span class = "error">Please provide a valid telephone or email</span>
    </label>
    <input type = "submit" value = "Send" />
</form>

CSS:

label {
    position: relative;
}

.error {
    position: absolute;
    white-space: nowrap;
    bottom: -8px;
    left: 0;
    transform: translateY(100%);
    display: none;
    background-color: hsla(0, 50%, 70%, 1);
    padding: 5px 10px;
    border-radius: 5px;
    font: normal 12px/1 Sans-Serif;
}

.error:before {
    content: "";
    position: absolute;
    border-style: solid;
    border-color: transparent transparent hsla(0, 50%, 70%, 1) transparent;
    border-width: 0 5px 5px 5px;
    left: 15px;
    top: -5px;
}

input {
    outline: 0;
}

input:invalid + .error {
    display: block;
}