[FIX] web: compute the correct height for textarea autoresize

The box-sizing property was not correctly taken into account.

- content-box is the standard behavior: border and padding are added after the height
- border-box needs attention: border and padding must be included into the computed height

Task: 1869469
PR: #26430

1 files changed, 5 insertions, 5 deletions

diff --git a/addons/web/static/src/js/core/dom.js b/addons/web/static/src/js/core/dom.js
index 7e3cb6128b9..eaff2185de9 100644
--- a/addons/web/static/src/js/core/dom.js
+++ b/addons/web/static/src/js/core/dom.js
@@ -74,12 +74,12 @@ return {
 
         function resize() {
             $fixedTextarea.insertAfter($textarea);
-            var heightOffset;
+            var heightOffset = 0;
             var style = window.getComputedStyle($textarea[0], null);
-            if (style.boxSizing === 'content-box') {
-                heightOffset = -(parseFloat(style.paddingTop) + parseFloat(style.paddingBottom));
-            } else {
-                heightOffset = parseFloat(style.borderTopWidth) + parseFloat(style.borderBottomWidth);
+            if (style.boxSizing === 'border-box') {
+                var paddingHeight = parseFloat(style.paddingTop) + parseFloat(style.paddingBottom);
+                var borderHeight = parseFloat(style.borderTopWidth) + parseFloat(style.borderBottomWidth);
+                heightOffset = borderHeight + paddingHeight;
             }
             $fixedTextarea.width($textarea.width());
             $fixedTextarea.val($textarea.val());