diff --git a/static/script.js b/static/script.js
index ad849ac..ca75f3c 100644
--- a/static/script.js
+++ b/static/script.js
@@ -92,8 +92,8 @@ function save(partID) {
 	var quantity_v = $('#quantity-input').val();
 	var notes_v = $('#notes-input').val();
 	var datasheet = $('#datasheet-input')[0].files;
-	if(! partno_v.match(/^([a-zA-Z0-9]+\s*){1,3}$/g)) {
-		alert('Invalid part number format. Accepted: <Part-number-line-1> <Part-number-line-2> <Part-number-line-3>');
+	if(! partno_v.match(/^([a-zA-Z0-9]{1,20}\s*){1,3}$/g)) {
+		alert('Invalid part number format. Accepted: <Part-number-line-1(max 20 chars)> <Part-number-line-2(max 20 chars)> <Part-number-line-3(max 20 chars)>');
 		return;
 	}
 	if(! block_v.match(/^[0-9]+$/g)) {