From 6490b113d8f0e0ca4f7835e703593024f7adc332 Mon Sep 17 00:00:00 2001
From: damianedwards <damian@damianedwards.com>
Date: Thu, 26 Feb 2015 17:56:47 -0800
Subject: [PATCH] Make LinkTagHelper JS down-level browser safe: - #2088

---
 .../js/LinkTagHelper_FallbackJavaScript.js           |  5 ++++-
 .../MvcTagHelpersWebSite.MvcTagHelper_Home.Link.html | 12 ++++++------
 2 files changed, 10 insertions(+), 7 deletions(-)

diff --git a/src/Microsoft.AspNet.Mvc.TagHelpers/js/LinkTagHelper_FallbackJavaScript.js b/src/Microsoft.AspNet.Mvc.TagHelpers/js/LinkTagHelper_FallbackJavaScript.js
index e68f3a92d5..45e5180233 100644
--- a/src/Microsoft.AspNet.Mvc.TagHelpers/js/LinkTagHelper_FallbackJavaScript.js
+++ b/src/Microsoft.AspNet.Mvc.TagHelpers/js/LinkTagHelper_FallbackJavaScript.js
@@ -16,9 +16,12 @@
         scriptElements = doc.getElementsByTagName("SCRIPT"),
         // Find the meta tag before this script tag, that's the element we're going to test the CSS property on
         meta = scriptElements[scriptElements.length - 1].previousElementSibling,
+        // Get the current style of the meta tag starting with standards-based API and falling back to <=IE8 API
+        metaStyle = (doc.defaultView && doc.defaultView.getComputedStyle) ? doc.defaultView.getComputedStyle(meta)
+            : meta.currentStyle,
         i;
 
-    if (doc.defaultView.getComputedStyle(meta)[cssTestPropertyName] !== cssTestPropertyValue) {
+    if (metaStyle && metaStyle[cssTestPropertyName] !== cssTestPropertyValue) {
         for (i = 0; i < fallbackHref.length; i++) {
             doc.write('<link rel="stylesheet" href="' + fallbackHref[i] + '"/>');
         }
diff --git a/test/Microsoft.AspNet.Mvc.FunctionalTests/Compiler/Resources/MvcTagHelpersWebSite.MvcTagHelper_Home.Link.html b/test/Microsoft.AspNet.Mvc.FunctionalTests/Compiler/Resources/MvcTagHelpersWebSite.MvcTagHelper_Home.Link.html
index 9c4e58721b..76fee781c2 100644
--- a/test/Microsoft.AspNet.Mvc.FunctionalTests/Compiler/Resources/MvcTagHelpersWebSite.MvcTagHelper_Home.Link.html
+++ b/test/Microsoft.AspNet.Mvc.FunctionalTests/Compiler/Resources/MvcTagHelpersWebSite.MvcTagHelper_Home.Link.html
@@ -37,27 +37,27 @@
 
     <!-- Fallback to static href -->
     <link href="/site.min.css" rel="stylesheet" data-extra="test" />
-<meta name="x-stylesheet-fallback-test" class="hidden" /><script>!function(a,b,c){var d,e=document,f=e.getElementsByTagName("SCRIPT"),g=f[f.length-1].previousElementSibling;if(e.defaultView.getComputedStyle(g)[a]!==b)for(d=0;d<c.length;d++)e.write('<link rel="stylesheet" href="'+c[d]+'"/>')}("visibility","hidden",["\/site.css"]);</script>
+<meta name="x-stylesheet-fallback-test" class="hidden" /><script>!function(a,b,c){var d,e=document,f=e.getElementsByTagName("SCRIPT"),g=f[f.length-1].previousElementSibling,h=e.defaultView&&e.defaultView.getComputedStyle?e.defaultView.getComputedStyle(g):g.currentStyle;if(h&&h[a]!==b)for(d=0;d<c.length;d++)e.write('<link rel="stylesheet" href="'+c[d]+'"/>')}("visibility","hidden",["\/site.css"]);</script>
 
     <!-- Fallback to static href with no primary href -->
     <link rel="stylesheet" data-extra="test" />
-<meta name="x-stylesheet-fallback-test" class="hidden" /><script>!function(a,b,c){var d,e=document,f=e.getElementsByTagName("SCRIPT"),g=f[f.length-1].previousElementSibling;if(e.defaultView.getComputedStyle(g)[a]!==b)for(d=0;d<c.length;d++)e.write('<link rel="stylesheet" href="'+c[d]+'"/>')}("visibility","hidden",["\/site.css"]);</script>
+<meta name="x-stylesheet-fallback-test" class="hidden" /><script>!function(a,b,c){var d,e=document,f=e.getElementsByTagName("SCRIPT"),g=f[f.length-1].previousElementSibling,h=e.defaultView&&e.defaultView.getComputedStyle?e.defaultView.getComputedStyle(g):g.currentStyle;if(h&&h[a]!==b)for(d=0;d<c.length;d++)e.write('<link rel="stylesheet" href="'+c[d]+'"/>')}("visibility","hidden",["\/site.css"]);</script>
 
     <!-- Fallback to globbed href -->
     <link href="/site.min.css" rel="stylesheet" data-extra="test" />
-<meta name="x-stylesheet-fallback-test" class="hidden" /><script>!function(a,b,c){var d,e=document,f=e.getElementsByTagName("SCRIPT"),g=f[f.length-1].previousElementSibling;if(e.defaultView.getComputedStyle(g)[a]!==b)for(d=0;d<c.length;d++)e.write('<link rel="stylesheet" href="'+c[d]+'"/>')}("visibility","hidden",["\/site.css"]);</script>
+<meta name="x-stylesheet-fallback-test" class="hidden" /><script>!function(a,b,c){var d,e=document,f=e.getElementsByTagName("SCRIPT"),g=f[f.length-1].previousElementSibling,h=e.defaultView&&e.defaultView.getComputedStyle?e.defaultView.getComputedStyle(g):g.currentStyle;if(h&&h[a]!==b)for(d=0;d<c.length;d++)e.write('<link rel="stylesheet" href="'+c[d]+'"/>')}("visibility","hidden",["\/site.css"]);</script>
 
     <!-- Fallback to static and globbed href -->
     <link href="/site.min.css" rel="stylesheet" data-extra="test" />
-<meta name="x-stylesheet-fallback-test" class="hidden" /><script>!function(a,b,c){var d,e=document,f=e.getElementsByTagName("SCRIPT"),g=f[f.length-1].previousElementSibling;if(e.defaultView.getComputedStyle(g)[a]!==b)for(d=0;d<c.length;d++)e.write('<link rel="stylesheet" href="'+c[d]+'"/>')}("visibility","hidden",["\/site.css","\/sub\/site2.css"]);</script>
+<meta name="x-stylesheet-fallback-test" class="hidden" /><script>!function(a,b,c){var d,e=document,f=e.getElementsByTagName("SCRIPT"),g=f[f.length-1].previousElementSibling,h=e.defaultView&&e.defaultView.getComputedStyle?e.defaultView.getComputedStyle(g):g.currentStyle;if(h&&h[a]!==b)for(d=0;d<c.length;d++)e.write('<link rel="stylesheet" href="'+c[d]+'"/>')}("visibility","hidden",["\/site.css","\/sub\/site2.css"]);</script>
 
     <!-- Fallback to static and globbed href should dedupe -->
     <link href="/site.min.css" rel="stylesheet" data-extra="test" />
-<meta name="x-stylesheet-fallback-test" class="hidden" /><script>!function(a,b,c){var d,e=document,f=e.getElementsByTagName("SCRIPT"),g=f[f.length-1].previousElementSibling;if(e.defaultView.getComputedStyle(g)[a]!==b)for(d=0;d<c.length;d++)e.write('<link rel="stylesheet" href="'+c[d]+'"/>')}("visibility","hidden",["\/site.css"]);</script>
+<meta name="x-stylesheet-fallback-test" class="hidden" /><script>!function(a,b,c){var d,e=document,f=e.getElementsByTagName("SCRIPT"),g=f[f.length-1].previousElementSibling,h=e.defaultView&&e.defaultView.getComputedStyle?e.defaultView.getComputedStyle(g):g.currentStyle;if(h&&h[a]!==b)for(d=0;d<c.length;d++)e.write('<link rel="stylesheet" href="'+c[d]+'"/>')}("visibility","hidden",["\/site.css"]);</script>
 
     <!-- Fallback to static and globbed href with exclude -->
     <link href="/site.min.css" rel="stylesheet" data-extra="test" />
-<meta name="x-stylesheet-fallback-test" class="hidden" /><script>!function(a,b,c){var d,e=document,f=e.getElementsByTagName("SCRIPT"),g=f[f.length-1].previousElementSibling;if(e.defaultView.getComputedStyle(g)[a]!==b)for(d=0;d<c.length;d++)e.write('<link rel="stylesheet" href="'+c[d]+'"/>')}("visibility","hidden",["\/site.css","\/sub\/site2.css"]);</script>
+<meta name="x-stylesheet-fallback-test" class="hidden" /><script>!function(a,b,c){var d,e=document,f=e.getElementsByTagName("SCRIPT"),g=f[f.length-1].previousElementSibling,h=e.defaultView&&e.defaultView.getComputedStyle?e.defaultView.getComputedStyle(g):g.currentStyle;if(h&&h[a]!==b)for(d=0;d<c.length;d++)e.write('<link rel="stylesheet" href="'+c[d]+'"/>')}("visibility","hidden",["\/site.css","\/sub\/site2.css"]);</script>
 
     <!-- Fallback to globbed href that doesn't exist -->
     <link href="/site.min.css" rel="stylesheet" data-extra="test" />