Index: django/template/defaultfilters.py
===================================================================
--- django/template/defaultfilters.py	(revision 5061)
+++ django/template/defaultfilters.py	(working copy)
@@ -47,7 +47,7 @@
 
 def addslashes(value):
     "Adds slashes - useful for passing strings to JavaScript, for example."
-    return value.replace('\\', '\\\\').replace('"', '\\"').replace("'", "\\'")
+    return value.replace('\\', '\\\\').replace('"', '\\"').replace("'", "\\'").replace("</", "<\\/")
 addslashes = stringfilter(addslashes)
 
 def capfirst(value):
Index: tests/regressiontests/defaultfilters/tests.py
===================================================================
--- tests/regressiontests/defaultfilters/tests.py	(revision 5061)
+++ tests/regressiontests/defaultfilters/tests.py	(working copy)
@@ -40,6 +40,9 @@
 >>> addslashes(r'\ : backslashes, too')
 '\\\\ : backslashes, too'
 
+>>> addslashes('<script>alert("make sure close tags are ok")</script>')
+'<script>alert(\\"make sure close tags are ok\\")<\\/script>'
+
 >>> capfirst('hello world')
 'Hello world'