diff --git a/mozilla/content/html/content/src/nsGenericHTMLElement.cpp b/mozilla/content/html/content/src/nsGenericHTMLElement.cpp
index 9f5a6cda0c2..2831f2bcbde 100644
--- a/mozilla/content/html/content/src/nsGenericHTMLElement.cpp
+++ b/mozilla/content/html/content/src/nsGenericHTMLElement.cpp
@@ -2428,7 +2428,7 @@ static const nsAttrValue::EnumTable kVAlignTable[] = {
 };
 
 static const nsAttrValue::EnumTable kDivAlignTable[] = {
-  { "left", NS_STYLE_TEXT_ALIGN_LEFT },
+  { "left", NS_STYLE_TEXT_ALIGN_MOZ_LEFT },
   { "right", NS_STYLE_TEXT_ALIGN_MOZ_RIGHT },
   { "center", NS_STYLE_TEXT_ALIGN_MOZ_CENTER },
   { "middle", NS_STYLE_TEXT_ALIGN_MOZ_CENTER },
@@ -2509,7 +2509,7 @@ nsGenericHTMLElement::ParseTableHAlignValue(const nsAString& aString,
 
 // These tables are used for TD,TH,TR, etc (but not TABLE)
 static const nsAttrValue::EnumTable kTableCellHAlignTable[] = {
-  { "left",   NS_STYLE_TEXT_ALIGN_LEFT },
+  { "left",   NS_STYLE_TEXT_ALIGN_MOZ_LEFT },
   { "right",  NS_STYLE_TEXT_ALIGN_MOZ_RIGHT },
   { "center", NS_STYLE_TEXT_ALIGN_MOZ_CENTER },
   { "char",   NS_STYLE_TEXT_ALIGN_CHAR },
@@ -2518,7 +2518,7 @@ static const nsAttrValue::EnumTable kTableCellHAlignTable[] = {
 };
 
 static const nsAttrValue::EnumTable kCompatTableCellHAlignTable[] = {
-  { "left",   NS_STYLE_TEXT_ALIGN_LEFT },
+  { "left",   NS_STYLE_TEXT_ALIGN_MOZ_LEFT },
   { "right",  NS_STYLE_TEXT_ALIGN_MOZ_RIGHT },
   { "center", NS_STYLE_TEXT_ALIGN_MOZ_CENTER },
   { "char",   NS_STYLE_TEXT_ALIGN_CHAR },
diff --git a/mozilla/layout/base/nsStyleConsts.h b/mozilla/layout/base/nsStyleConsts.h
index cedadc02816..e877693ed23 100644
--- a/mozilla/layout/base/nsStyleConsts.h
+++ b/mozilla/layout/base/nsStyleConsts.h
@@ -526,6 +526,7 @@
 #define NS_STYLE_TEXT_ALIGN_CHAR                5   //align based on a certain character, for table cell
 #define NS_STYLE_TEXT_ALIGN_MOZ_CENTER          6
 #define NS_STYLE_TEXT_ALIGN_MOZ_RIGHT           7
+#define NS_STYLE_TEXT_ALIGN_MOZ_LEFT            8
 
 // See nsStyleText, nsStyleFont
 #define NS_STYLE_TEXT_DECORATION_NONE           0
diff --git a/mozilla/layout/generic/nsBlockReflowContext.cpp b/mozilla/layout/generic/nsBlockReflowContext.cpp
index 680c149c824..7993a89adc8 100644
--- a/mozilla/layout/generic/nsBlockReflowContext.cpp
+++ b/mozilla/layout/generic/nsBlockReflowContext.cpp
@@ -268,7 +268,7 @@ nsBlockReflowContext::AlignBlockHorizontally(nscoord                 aWidth,
           aAlign.mXOffset += remainingSpace;
         } else if (styleText->mTextAlign == NS_STYLE_TEXT_ALIGN_MOZ_CENTER) {
           aAlign.mXOffset += remainingSpace / 2;
-        } else {
+        } else if (styleText->mTextAlign != NS_STYLE_TEXT_ALIGN_MOZ_LEFT) {
           // If we don't have a special text-align value indicating
           // HTML alignment, then use the CSS rules.
 
diff --git a/mozilla/layout/generic/nsHTMLReflowState.cpp b/mozilla/layout/generic/nsHTMLReflowState.cpp
index e29daea156f..898904b17ca 100644
--- a/mozilla/layout/generic/nsHTMLReflowState.cpp
+++ b/mozilla/layout/generic/nsHTMLReflowState.cpp
@@ -2165,11 +2165,13 @@ nsHTMLReflowState::CalculateBlockSideMargins(nscoord aAvailWidth,
     // First check if there is an HTML alignment that we should honor
     const nsHTMLReflowState* prs = parentReflowState;
     if (prs &&
-        (prs->mStyleText->mTextAlign == NS_STYLE_TEXT_ALIGN_MOZ_CENTER ||
+        (prs->mStyleText->mTextAlign == NS_STYLE_TEXT_ALIGN_MOZ_LEFT ||
+         prs->mStyleText->mTextAlign == NS_STYLE_TEXT_ALIGN_MOZ_CENTER ||
          prs->mStyleText->mTextAlign == NS_STYLE_TEXT_ALIGN_MOZ_RIGHT)) {
-      isAutoLeftMargin = PR_TRUE;
+      isAutoLeftMargin =
+        prs->mStyleText->mTextAlign != NS_STYLE_TEXT_ALIGN_MOZ_LEFT;
       isAutoRightMargin =
-        prs->mStyleText->mTextAlign == NS_STYLE_TEXT_ALIGN_MOZ_CENTER;
+        prs->mStyleText->mTextAlign != NS_STYLE_TEXT_ALIGN_MOZ_RIGHT;
     }
     // Otherwise apply the CSS rules, and ignore one margin by forcing
     // it to 'auto', depending on 'direction'.
diff --git a/mozilla/layout/generic/nsLineLayout.cpp b/mozilla/layout/generic/nsLineLayout.cpp
index fce6c484e39..d501aaceb99 100644
--- a/mozilla/layout/generic/nsLineLayout.cpp
+++ b/mozilla/layout/generic/nsLineLayout.cpp
@@ -2830,6 +2830,7 @@ nsLineLayout::HorizontalAlignFrames(nsRect& aLineBounds,
         break;
 
       case NS_STYLE_TEXT_ALIGN_LEFT:
+      case NS_STYLE_TEXT_ALIGN_MOZ_LEFT:
         break;
 
       case NS_STYLE_TEXT_ALIGN_JUSTIFY:
diff --git a/mozilla/layout/style/nsCSSKeywordList.h b/mozilla/layout/style/nsCSSKeywordList.h
index da22d435583..52d2c1a94d6 100644
--- a/mozilla/layout/style/nsCSSKeywordList.h
+++ b/mozilla/layout/style/nsCSSKeywordList.h
@@ -126,6 +126,7 @@ CSS_KEY(-moz-japanese-informal, _moz_japanese_informal)
 CSS_KEY(-moz-kannada, _moz_kannada)
 CSS_KEY(-moz-khmer, _moz_khmer)
 CSS_KEY(-moz-lao, _moz_lao)
+CSS_KEY(-moz-left, _moz_left)
 CSS_KEY(-moz-list, _moz_list)
 CSS_KEY(-moz-mac-accentdarkestshadow, _moz_mac_accentdarkestshadow)
 CSS_KEY(-moz-mac-accentdarkshadow, _moz_mac_accentdarkshadow)
diff --git a/mozilla/layout/style/nsCSSProps.cpp b/mozilla/layout/style/nsCSSProps.cpp
index 50f19fcc015..98478bb7ca8 100644
--- a/mozilla/layout/style/nsCSSProps.cpp
+++ b/mozilla/layout/style/nsCSSProps.cpp
@@ -829,6 +829,7 @@ const PRInt32 nsCSSProps::kTextAlignKTable[] = {
   eCSSKeyword_justify, NS_STYLE_TEXT_ALIGN_JUSTIFY,
   eCSSKeyword__moz_center, NS_STYLE_TEXT_ALIGN_MOZ_CENTER,
   eCSSKeyword__moz_right, NS_STYLE_TEXT_ALIGN_MOZ_RIGHT,
+  eCSSKeyword__moz_left, NS_STYLE_TEXT_ALIGN_MOZ_LEFT,
   eCSSKeyword_start, NS_STYLE_TEXT_ALIGN_DEFAULT,
   eCSSKeyword_UNKNOWN,-1
 };