input-field

I am creating an HTML5 application on an Android and for this specific scenario, we have an input field that is for a credit card's security code and we want to force the input field to be numberic only and masked. I have had no luck searching for this specific case and from everything I can tell from researching/trying it out for myself is that this can't be done purely through HTML5 (since number and password are both options for type and only one type can be used). Am I missing something and there is a way to pop-up the numeric keyboard while having the input be masked through HTML5 or is

As Most, I am familiar with the readonly attribute for text input , But while reading code from other websites (a nasty habit of mine ) I saw more than one implementation for this attribute: <input type="text" value="myvalue" class="class anotherclass" readonly > and <input type="text" value="myvalue" class="class anotherclass" readonly="readonly" > and I have even seen <input type="text" value="myvalue" class="class anotherclass" readonly="true" > .. And I believe I saw even more, but can not recall the exact syntax now.. So, which one is the correct one that I should use? Vucko From w3 :

using jQuery here, however unable to prevent numbers from being typed into the input field http://codepen.io/leongaban/pen/owbjg Input <input type="text" name="field" maxlength="8" title="Only Letters" value="Type Letters Only" onkeydown="return alphaOnly(event);" onblur="if (this.value == '') {this.value = 'Type Letters Only';}" onfocus="if (this.value == 'Type Letters Only') {this.value = '';}"/> jQuery function alphaOnly(event) { alert(event); var key; if (window.event) { key = window.event.key; } else if (e) { key = e.which; } //var key = window.event.key || event.key; alert(key.value);