4 files changed, 43 insertions, 8 deletions

diff --git a/web/react/components/create_comment.jsx b/web/react/components/create_comment.jsx
index 59b0a5c2b..68bee800a 100644
--- a/web/react/components/create_comment.jsx
+++ b/web/react/components/create_comment.jsx
@@ -108,9 +108,11 @@ module.exports = React.createClass({
     handleUserInput: function(messageText) {
         var newPostError = this.state.postError;
 
-        if (!this.state.postError && messageText.length >= Constants.MAX_POST_LEN) {
-            newPostError = 'Message length cannot exceed 4000 characters';
-        } else if (this.state.postError === 'Message length cannot exceed 4000 characters' && messageText.length < Constants.MAX_POST_LEN) {
+        var len = utils.getLengthOfTextInTextarea(messageText);
+
+        if (!this.state.postError && len >= Constants.MAX_POST_LEN) {
+            newPostError = 'Comment length cannot exceed 4000 characters';
+        } else if (this.state.postError === 'Comment length cannot exceed 4000 characters' && len < Constants.MAX_POST_LEN) {
             newPostError = '';
         }
 
diff --git a/web/react/components/create_post.jsx b/web/react/components/create_post.jsx
index 242513d07..387149b14 100644
--- a/web/react/components/create_post.jsx
+++ b/web/react/components/create_post.jsx
@@ -134,9 +134,11 @@ module.exports = React.createClass({
     handleUserInput: function(messageText) {
         var newPostError = this.state.postError;
 
-        if (!this.state.postError && messageText.length >= Constants.MAX_POST_LEN) {
+        var len = utils.getLengthOfTextInTextarea(messageText);
+
+        if (!this.state.postError && len >= Constants.MAX_POST_LEN) {
             newPostError = 'Message length cannot exceed 4000 characters';
-        } else if (this.state.postError === 'Message length cannot exceed 4000 characters' && messageText.length < Constants.MAX_POST_LEN) {
+        } else if (this.state.postError === 'Message length cannot exceed 4000 characters' && len < Constants.MAX_POST_LEN) {
             newPostError = '';
         }
 
diff --git a/web/react/components/edit_post_modal.jsx b/web/react/components/edit_post_modal.jsx
index 2dce889f8..39d058f30 100644
--- a/web/react/components/edit_post_modal.jsx
+++ b/web/react/components/edit_post_modal.jsx
@@ -4,6 +4,7 @@
 var Client = require('../utils/client.jsx');
 var AsyncClient = require('../utils/async_client.jsx');
 var Constants = require('../utils/constants.jsx');
+var utils = require('../utils/utils.jsx');
 var Textbox = require('./textbox.jsx');
 var BrowserStore = require('../stores/browser_store.jsx');
 
@@ -40,9 +41,11 @@ module.exports = React.createClass({
     handleEditInput: function(editText) {
         var newError = this.state.error;
 
-        if (!this.state.error && editText.length >= Constants.MAX_POST_LEN) {
-            newError = 'Message length cannot exceed 4000 characters';
-        } else if (this.state.error === 'Message length cannot exceed 4000 characters' && editText.length < Constants.MAX_POST_LEN) {
+        var len = utils.getLengthOfTextInTextarea(editText);
+
+        if (!this.state.error && len >= Constants.MAX_POST_LEN) {
+            newError = 'New message length cannot exceed 4000 characters';
+        } else if (this.state.error === 'New message length cannot exceed 4000 characters' && len < Constants.MAX_POST_LEN) {
             newError = '';
         }
 
diff --git a/web/react/utils/utils.jsx b/web/react/utils/utils.jsx
index f718f7435..33c103c2e 100644
--- a/web/react/utils/utils.jsx
+++ b/web/react/utils/utils.jsx
@@ -1004,6 +1004,34 @@ module.exports.isBrowserFirefox = function() {
     return navigator && navigator.userAgent && navigator.userAgent.toLowerCase().indexOf('firefox') > -1;
 };
 
+// Checks if browser is IE10 or IE11
+module.exports.isBrowserIE = function() {
+    if (window.navigator && window.navigator.userAgent) {
+        var ua = window.navigator.userAgent;
+
+        return ua.indexOf('Trident/7.0') > 0 || ua.indexOf('Trident/6.0') > 0;
+    }
+
+    return false;
+};
+
+module.exports.isBrowserEdge = function() {
+    return window.naviagtor && navigator.userAgent && navigator.userAgent.toLowerCase().indexOf('edge') > -1;
+};
+
+// Gets text length consistent with maxlength property of textarea html tag
+module.exports.getLengthOfTextInTextarea = function(messageText) {
+    // Need to get length with carriage returns counting as two characters to match textbox maxlength behavior
+    // unless ie10/ie11/edge which already do
+
+    var len = messageText.length;
+    if (!module.exports.isBrowserIE() && !module.exports.isBrowserEdge()) {
+        len = messageText.replace(/\r(?!\n)|\n(?!\r)/g, '--').length;
+    }
+
+    return len;
+};
+
 // Used to get the id of the other user from a DM channel
 module.exports.getUserIdFromChannelName = function(channel) {
     var ids = channel.name.split('__');