How Do I Get An Input Alert Message To Work Only When Imputing Alphabets, Not For Numbers? Without Letting Any Text Tipped In

How do I get an input alert message to work only when imputing alphabets, not for numbers? Without letting any text tipped in. When imputing numbers there should be no alerts, but

Solution 1:

You need to use preventDefault() if you want to to cancel the event, that is to disallow text box from accepting non-numeric input. So that you don't have to bother about deleting it. However, preventDefault() does not work with onkeyup. Use onkeydown.

JS:

function checkKey(e) 
{
    if (e.keyCode != 8 && // allow backspace
        e.keyCode != 46 && // allow delete
        e.keyCode != 37 && // allow left arrow
        e.keyCode != 39 && // allow right arrow
        (e.keyCode < 48 || e.keyCode > 57)) // allow numerics only
    {
        e.preventDefault();
    }
}

HTML:

<input type="text" onkeydown="checkKey(event)" />

Note - Alerting user on each key press / down / up is terrible. Simply annoying. Avoid! Silently block the unwanted keys as I showed above.

Solution 2:

Put a regular expression test in the onkeyup attribute.

onkeyup="if(/\D/.test(this.value)) alert('no text here, input numbers only')"

Solution 3:

By playing around and mixing with different codes I found the answer on my own. I made a filter who lets only the characters chosen by me in the box and then added a alert message to it and WHALA there it works.

This is the answer I found:

JavaScript:

<script language="javascript" type="text/javascript">
function TextFilter(myfield, e)
{
    var key;
    var keychar;
    if (window.event)
    key = window.event.keyCode;
    else if (e)
    key = e.which;
    else
    return true;
    keychar = String.fromCharCode(key);

    if ((key==null) || (key==0) || (key==8) || (key==9) || (key==13) || (key==27) )
    return true;

    else if ((("0123456789.").indexOf(keychar) > -1))
    return true;

    else if ((keychar == ""))
    {
        if (myfield.value.indexOf(keychar) > -1)
        return false;
    }
    else
    return false;
}

function checkInp()
{
    var x = document.forms["isnform04"]["areinp"].value;
    var regex = /^[0-9]+$/;
    if (!x.match(regex))
    {
        alert("no text here, input numbers only");
        return false;
    }
}
</script>

HTML:

<input type="text" name="areinp" id="test" size="30" value="" onChange="areCon()" onkeypress="return TextFilter(this, event)" onkeyup="checkInp()">