How to restrict a field to accept first 2 char. as alphabets and last 5 numbers

[KS13]

Yesterday, a solution was provided for the same question, but after the error message was closed, it still allowed the user to submit with the inaccurate format. 

Have written the following script and still not working:

function onChange(control, oldValue, newValue, isLoading) {
if (isLoading || newValue == '') {
return;
}

var rexp = '/^[a-zA-Z]{2}[0-9]{5}]$/';   
var dataValue=g_form.getValue('provide_id');

if (dataValue.match(rexp)==null){
alert('The new  ID format does match the ID format.');
g_form.clearValue('provide_id');
g_form.showFieldMsg('provide_id', 'The new  ID format does match the ID format.', 'info', true);
} else {
g_form.clearMessages();
}
}

[Brad Bowman]

That regex should work, but I fought with it for a little bit and couldn't figure it out.  Here's a script that works:

function onChange(control, oldValue, newValue, isLoading, isTemplate) {
    if (isLoading || newValue === '') {
        return;
    }
    
	var rexp = /^[a-zA-Z]{2}\d{5}$/;   
    var dataValue = rexp.exec(newValue);

    if (dataValue === null){
		alert('The new  ID format does match the ID format.');
		g_form.clearValue('provide_id');
		g_form.showFieldMsg('provide_id', 'The new  ID format does match the ID format.', 'info', true);
    } else {
		g_form.clearMessages();
    }
}

[KS13]

Thank you Brad, this worked perfectly! Much appreciated. 

[Brad Bowman]

Glad to hear.  You are welcome!

[Community Alums]

So, forst of all, you need to know the exact number of characters the user is typing. So, if you have allowed total lenght of 10 chars, you need to check if the first 2 are letters + whatever chars here (3 chars in total) + 5 number chars.

This means you need to check this somehow. I had similar requirement in the past and ended with onLoad client script, but my solution was to check for some forbiden characters (but still kep the already typed in input). I will send a link to the solution, but it must be changed a bit to handle your needs. Will try this in a moment. In the mean time - here is the link:
https://www.servicenow.com/community/now-platform-articles/escape-special-characters-without-loosing...

[Community Alums]

Try something like this (tested it quite fast so you have to test it yourself)

function onLoad() {

var control = g_form.getControl('description');
Event.observe(control, 'input', function(e) {
	
	var oldInputVal = e.target.defaultValue;
	var newInputVal = e.target.value;
	//var regexSpecialChars = /\/|\\|\"|;|<|>|\||\t|~|#|\*|:|\?|{|}|\s/gm;
	var regexMandatoryChars = /[a-zA-Z]{2}.{3}\d{5}/gm; //if you need only 2 chars + 5 digits - remove the .{3} part of teh regex

	var oldInput = (function () {			
		var i = oldInputVal;

		return {
			get: function () {
				return i;
			},
			set: function (val) {
				
				i = val;
			}
		};
	})();
	
	var userVal = newInputVal;//.replace(regexSpecialChars, "");
	if(newInputVal.length == 10){
	if(!regexMandatoryChars.test(userVal)){
		alert("NOPE " + userVal);
		
	} 
	} else if(newInputVal.length > 10){
		alert("No more chars allowed!")
		userVal = userVal.replace(/.$/, "");
	}
	oldInput.set(userVal);		
	g_form.setValue('description', oldInput.get());
	

});

}