Fixed issue with carriage returns being counted improperly in non-ie browsers and updated error messages to be appropriate to what is being typed (message vs. post vs. edit)

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('__');