diff --git a/api/next/61619.txt b/api/next/61619.txt
new file mode 100644
index 0000000000..c63a3140e8
--- /dev/null
+++ b/api/next/61619.txt
@@ -0,0 +1 @@
+pkg html/template, const ErrJSTemplate //deprecated #61619
diff --git a/src/html/template/context.go b/src/html/template/context.go
index 16b5e65317..63d5c31b01 100644
--- a/src/html/template/context.go
+++ b/src/html/template/context.go
@@ -17,14 +17,16 @@ import (
 // https://www.w3.org/TR/html5/syntax.html#the-end
 // where the context element is null.
 type context struct {
-	state   state
-	delim   delim
-	urlPart urlPart
-	jsCtx   jsCtx
-	attr    attr
-	element element
-	n       parse.Node // for range break/continue
-	err     *Error
+	state           state
+	delim           delim
+	urlPart         urlPart
+	jsCtx           jsCtx
+	jsTmplExprDepth int
+	jsBraceDepth    int
+	attr            attr
+	element         element
+	n               parse.Node // for range break/continue
+	err             *Error
 }
 
 func (c context) String() string {
@@ -120,8 +122,8 @@ const (
 	stateJSDqStr
 	// stateJSSqStr occurs inside a JavaScript single quoted string.
 	stateJSSqStr
-	// stateJSBqStr occurs inside a JavaScript back quoted string.
-	stateJSBqStr
+	// stateJSTmplLit occurs inside a JavaScript back quoted string.
+	stateJSTmplLit
 	// stateJSRegexp occurs inside a JavaScript regexp literal.
 	stateJSRegexp
 	// stateJSBlockCmt occurs inside a JavaScript /* block comment */.
@@ -182,7 +184,7 @@ func isInScriptLiteral(s state) bool {
 	// stateJSHTMLOpenCmt, stateJSHTMLCloseCmt) because their content is already
 	// omitted from the output.
 	switch s {
-	case stateJSDqStr, stateJSSqStr, stateJSBqStr, stateJSRegexp:
+	case stateJSDqStr, stateJSSqStr, stateJSTmplLit, stateJSRegexp:
 		return true
 	}
 	return false
diff --git a/src/html/template/error.go b/src/html/template/error.go
index a763924d4a..805a788bfc 100644
--- a/src/html/template/error.go
+++ b/src/html/template/error.go
@@ -221,6 +221,10 @@ const (
 	// Discussion:
 	//   Package html/template does not support actions inside of JS template
 	//   literals.
+	//
+	// Deprecated: ErrJSTemplate is no longer returned when an action is present
+	// in a JS template literal. Actions inside of JS template literals are now
+	// escaped as expected.
 	ErrJSTemplate
 )
 
diff --git a/src/html/template/escape.go b/src/html/template/escape.go
index 01f6303a44..1eace16e25 100644
--- a/src/html/template/escape.go
+++ b/src/html/template/escape.go
@@ -62,22 +62,23 @@ func evalArgs(args ...any) string {
 
 // funcMap maps command names to functions that render their inputs safe.
 var funcMap = template.FuncMap{
-	"_html_template_attrescaper":     attrEscaper,
-	"_html_template_commentescaper":  commentEscaper,
-	"_html_template_cssescaper":      cssEscaper,
-	"_html_template_cssvaluefilter":  cssValueFilter,
-	"_html_template_htmlnamefilter":  htmlNameFilter,
-	"_html_template_htmlescaper":     htmlEscaper,
-	"_html_template_jsregexpescaper": jsRegexpEscaper,
-	"_html_template_jsstrescaper":    jsStrEscaper,
-	"_html_template_jsvalescaper":    jsValEscaper,
-	"_html_template_nospaceescaper":  htmlNospaceEscaper,
-	"_html_template_rcdataescaper":   rcdataEscaper,
-	"_html_template_srcsetescaper":   srcsetFilterAndEscaper,
-	"_html_template_urlescaper":      urlEscaper,
-	"_html_template_urlfilter":       urlFilter,
-	"_html_template_urlnormalizer":   urlNormalizer,
-	"_eval_args_":                    evalArgs,
+	"_html_template_attrescaper":      attrEscaper,
+	"_html_template_commentescaper":   commentEscaper,
+	"_html_template_cssescaper":       cssEscaper,
+	"_html_template_cssvaluefilter":   cssValueFilter,
+	"_html_template_htmlnamefilter":   htmlNameFilter,
+	"_html_template_htmlescaper":      htmlEscaper,
+	"_html_template_jsregexpescaper":  jsRegexpEscaper,
+	"_html_template_jsstrescaper":     jsStrEscaper,
+	"_html_template_jstmpllitescaper": jsTmplLitEscaper,
+	"_html_template_jsvalescaper":     jsValEscaper,
+	"_html_template_nospaceescaper":   htmlNospaceEscaper,
+	"_html_template_rcdataescaper":    rcdataEscaper,
+	"_html_template_srcsetescaper":    srcsetFilterAndEscaper,
+	"_html_template_urlescaper":       urlEscaper,
+	"_html_template_urlfilter":        urlFilter,
+	"_html_template_urlnormalizer":    urlNormalizer,
+	"_eval_args_":                     evalArgs,
 }
 
 // escaper collects type inferences about templates and changes needed to make
@@ -227,16 +228,8 @@ func (e *escaper) escapeAction(c context, n *parse.ActionNode) context {
 		c.jsCtx = jsCtxDivOp
 	case stateJSDqStr, stateJSSqStr:
 		s = append(s, "_html_template_jsstrescaper")
-	case stateJSBqStr:
-		if debugAllowActionJSTmpl.Value() == "1" {
-			debugAllowActionJSTmpl.IncNonDefault()
-			s = append(s, "_html_template_jsstrescaper")
-		} else {
-			return context{
-				state: stateError,
-				err:   errorf(ErrJSTemplate, n, n.Line, "%s appears in a JS template literal", n),
-			}
-		}
+	case stateJSTmplLit:
+		s = append(s, "_html_template_jstmpllitescaper")
 	case stateJSRegexp:
 		s = append(s, "_html_template_jsregexpescaper")
 	case stateCSS:
@@ -395,6 +388,9 @@ var redundantFuncs = map[string]map[string]bool{
 	"_html_template_jsstrescaper": {
 		"_html_template_attrescaper": true,
 	},
+	"_html_template_jstmpllitescaper": {
+		"_html_template_attrescaper": true,
+	},
 	"_html_template_urlescaper": {
 		"_html_template_urlnormalizer": true,
 	},
diff --git a/src/html/template/escape_test.go b/src/html/template/escape_test.go
index 8a4f62e92f..9e2f4fe922 100644
--- a/src/html/template/escape_test.go
+++ b/src/html/template/escape_test.go
@@ -30,14 +30,14 @@ func (x *goodMarshaler) MarshalJSON() ([]byte, error) {
 
 func TestEscape(t *testing.T) {
 	data := struct {
-		F, T    bool
-		C, G, H string
-		A, E    []string
-		B, M    json.Marshaler
-		N       int
-		U       any  // untyped nil
-		Z       *int // typed nil
-		W       HTML
+		F, T       bool
+		C, G, H, I string
+		A, E       []string
+		B, M       json.Marshaler
+		N          int
+		U          any  // untyped nil
+		Z          *int // typed nil
+		W          HTML
 	}{
 		F: false,
 		T: true,
@@ -52,6 +52,7 @@ func TestEscape(t *testing.T) {
 		U: nil,
 		Z: nil,
 		W: HTML(`&iexcl;<b class="foo">Hello</b>, <textarea>O'World</textarea>!`),
+		I: "${ asd `` }",
 	}
 	pdata := &data
 
@@ -718,6 +719,21 @@ func TestEscape(t *testing.T) {
 			"<p name=\"{{.U}}\">",
 			"<p name=\"\">",
 		},
+		{
+			"JS template lit special characters",
+			"<script>var a = `{{.I}}`</script>",
+			"<script>var a = `\\u0024\\u007b asd \\u0060\\u0060 \\u007d`</script>",
+		},
+		{
+			"JS template lit special characters, nested lit",
+			"<script>var a = `${ `{{.I}}` }`</script>",
+			"<script>var a = `${ `\\u0024\\u007b asd \\u0060\\u0060 \\u007d` }`</script>",
+		},
+		{
+			"JS template lit, nested JS",
+			"<script>var a = `${ var a = \"{{\"a \\\" d\"}}\" }`</script>",
+			"<script>var a = `${ var a = \"a \\u0022 d\" }`</script>",
+		},
 	}
 
 	for _, test := range tests {
@@ -976,6 +992,31 @@ func TestErrors(t *testing.T) {
 			"<script>var a = `${a+b}`</script>`",
 			"",
 		},
+		{
+			"<script>var tmpl = `asd`;</script>",
+			``,
+		},
+		{
+			"<script>var tmpl = `${1}`;</script>",
+			``,
+		},
+		{
+			"<script>var tmpl = `${return ``}`;</script>",
+			``,
+		},
+		{
+			"<script>var tmpl = `${return {{.}} }`;</script>",
+			``,
+		},
+		{
+			"<script>var tmpl = `${ let a = {1:1} {{.}} }`;</script>",
+			``,
+		},
+		{
+			"<script>var tmpl = `asd ${return \"{\"}`;</script>",
+			``,
+		},
+
 		// Error cases.
 		{
 			"{{if .Cond}}<a{{end}}",
@@ -1122,10 +1163,26 @@ func TestErrors(t *testing.T) {
 			// html is allowed since it is the last command in the pipeline, but urlquery is not.
 			`predefined escaper "urlquery" disallowed in template`,
 		},
-		{
-			"<script>var tmpl = `asd {{.}}`;</script>",
-			`{{.}} appears in a JS template literal`,
-		},
+		// {
+		// 	"<script>var tmpl = `asd {{.}}`;</script>",
+		// 	`{{.}} appears in a JS template literal`,
+		// },
+		// {
+		// 	"<script>var v = `${function(){return `{{.V}}+1`}()}`;</script>",
+		// 	`{{.V}} appears in a JS template literal`,
+		// },
+		// {
+		// 	"<script>var a = `asd ${function(){b = {1:2}; return`{{.}}`}}`</script>",
+		// 	`{{.}} appears in a JS template literal`,
+		// },
+		// {
+		// 	"<script>var tmpl = `${return `{{.}}`}`;</script>",
+		// 	`{{.}} appears in a JS template literal`,
+		// },
+		// {
+		// 	"<script>var tmpl = `${return {`{{.}}`}`;</script>",
+		// 	`{{.}} appears in a JS template literal`,
+		// },
 	}
 	for _, test := range tests {
 		buf := new(bytes.Buffer)
@@ -1349,7 +1406,7 @@ func TestEscapeText(t *testing.T) {
 		},
 		{
 			"<a onclick=\"`foo",
-			context{state: stateJSBqStr, delim: delimDoubleQuote, attr: attrScript},
+			context{state: stateJSTmplLit, delim: delimDoubleQuote, attr: attrScript},
 		},
 		{
 			`<A ONCLICK="'`,
@@ -1691,6 +1748,58 @@ func TestEscapeText(t *testing.T) {
 			`<svg:a svg:onclick="x()">`,
 			context{},
 		},
+		{
+			"<script>var a = `",
+			context{state: stateJSTmplLit, element: elementScript},
+		},
+		{
+			"<script>var a = `${",
+			context{state: stateJS, element: elementScript},
+		},
+		{
+			"<script>var a = `${}",
+			context{state: stateJSTmplLit, element: elementScript},
+		},
+		{
+			"<script>var a = `${`",
+			context{state: stateJSTmplLit, element: elementScript},
+		},
+		{
+			"<script>var a = `${var a = \"",
+			context{state: stateJSDqStr, element: elementScript},
+		},
+		{
+			"<script>var a = `${var a = \"`",
+			context{state: stateJSDqStr, element: elementScript},
+		},
+		{
+			"<script>var a = `${var a = \"}",
+			context{state: stateJSDqStr, element: elementScript},
+		},
+		{
+			"<script>var a = `${``",
+			context{state: stateJS, element: elementScript},
+		},
+		{
+			"<script>var a = `${`}",
+			context{state: stateJSTmplLit, element: elementScript},
+		},
+		{
+			"<script>`${ {} } asd`</script><script>`${ {} }",
+			context{state: stateJSTmplLit, element: elementScript},
+		},
+		{
+			"<script>var foo = `${ (_ => { return \"x\" })() + \"${",
+			context{state: stateJSDqStr, element: elementScript},
+		},
+		{
+			"<script>var a = `${ {</script><script>var b = `${ x }",
+			context{state: stateJSTmplLit, element: elementScript, jsCtx: jsCtxDivOp},
+		},
+		{
+			"<script>var foo = `x` + \"${",
+			context{state: stateJSDqStr, element: elementScript},
+		},
 	}
 
 	for _, test := range tests {
diff --git a/src/html/template/js.go b/src/html/template/js.go
index 717de4300c..b159af8e4b 100644
--- a/src/html/template/js.go
+++ b/src/html/template/js.go
@@ -238,6 +238,11 @@ func jsStrEscaper(args ...any) string {
 	return replace(s, jsStrReplacementTable)
 }
 
+func jsTmplLitEscaper(args ...any) string {
+	s, _ := stringify(args...)
+	return replace(s, jsBqStrReplacementTable)
+}
+
 // jsRegexpEscaper behaves like jsStrEscaper but escapes regular expression
 // specials so the result is treated literally when included in a regular
 // expression literal. /foo{{.X}}bar/ matches the string "foo" followed by
@@ -324,6 +329,31 @@ var jsStrReplacementTable = []string{
 	'\\': `\\`,
 }
 
+// jsBqStrReplacementTable is like jsStrReplacementTable except it also contains
+// the special characters for JS template literals: $, {, and }.
+var jsBqStrReplacementTable = []string{
+	0:    `\u0000`,
+	'\t': `\t`,
+	'\n': `\n`,
+	'\v': `\u000b`, // "\v" == "v" on IE 6.
+	'\f': `\f`,
+	'\r': `\r`,
+	// Encode HTML specials as hex so the output can be embedded
+	// in HTML attributes without further encoding.
+	'"':  `\u0022`,
+	'`':  `\u0060`,
+	'&':  `\u0026`,
+	'\'': `\u0027`,
+	'+':  `\u002b`,
+	'/':  `\/`,
+	'<':  `\u003c`,
+	'>':  `\u003e`,
+	'\\': `\\`,
+	'$':  `\u0024`,
+	'{':  `\u007b`,
+	'}':  `\u007d`,
+}
+
 // jsStrNormReplacementTable is like jsStrReplacementTable but does not
 // overencode existing escapes since this table has no entry for `\`.
 var jsStrNormReplacementTable = []string{
diff --git a/src/html/template/state_string.go b/src/html/template/state_string.go
index be7a920511..eed1e8bcc0 100644
--- a/src/html/template/state_string.go
+++ b/src/html/template/state_string.go
@@ -21,7 +21,7 @@ func _() {
 	_ = x[stateJS-10]
 	_ = x[stateJSDqStr-11]
 	_ = x[stateJSSqStr-12]
-	_ = x[stateJSBqStr-13]
+	_ = x[stateJSTmplLit-13]
 	_ = x[stateJSRegexp-14]
 	_ = x[stateJSBlockCmt-15]
 	_ = x[stateJSLineCmt-16]
@@ -39,9 +39,9 @@ func _() {
 	_ = x[stateDead-28]
 }
 
-const _state_name = "stateTextstateTagstateAttrNamestateAfterNamestateBeforeValuestateHTMLCmtstateRCDATAstateAttrstateURLstateSrcsetstateJSstateJSDqStrstateJSSqStrstateJSBqStrstateJSRegexpstateJSBlockCmtstateJSLineCmtstateJSHTMLOpenCmtstateJSHTMLCloseCmtstateCSSstateCSSDqStrstateCSSSqStrstateCSSDqURLstateCSSSqURLstateCSSURLstateCSSBlockCmtstateCSSLineCmtstateErrorstateDead"
+const _state_name = "stateTextstateTagstateAttrNamestateAfterNamestateBeforeValuestateHTMLCmtstateRCDATAstateAttrstateURLstateSrcsetstateJSstateJSDqStrstateJSSqStrstateJSTmplLitstateJSRegexpstateJSBlockCmtstateJSLineCmtstateJSHTMLOpenCmtstateJSHTMLCloseCmtstateCSSstateCSSDqStrstateCSSSqStrstateCSSDqURLstateCSSSqURLstateCSSURLstateCSSBlockCmtstateCSSLineCmtstateErrorstateDead"
 
-var _state_index = [...]uint16{0, 9, 17, 30, 44, 60, 72, 83, 92, 100, 111, 118, 130, 142, 154, 167, 182, 196, 214, 233, 241, 254, 267, 280, 293, 304, 320, 335, 345, 354}
+var _state_index = [...]uint16{0, 9, 17, 30, 44, 60, 72, 83, 92, 100, 111, 118, 130, 142, 156, 169, 184, 198, 216, 235, 243, 256, 269, 282, 295, 306, 322, 337, 347, 356}
 
 func (i state) String() string {
 	if i >= state(len(_state_index)-1) {
diff --git a/src/html/template/transition.go b/src/html/template/transition.go
index 432c365d3c..4ea803e428 100644
--- a/src/html/template/transition.go
+++ b/src/html/template/transition.go
@@ -27,8 +27,8 @@ var transitionFunc = [...]func(context, []byte) (context, int){
 	stateJS:             tJS,
 	stateJSDqStr:        tJSDelimited,
 	stateJSSqStr:        tJSDelimited,
-	stateJSBqStr:        tJSDelimited,
 	stateJSRegexp:       tJSDelimited,
+	stateJSTmplLit:      tJSTmpl,
 	stateJSBlockCmt:     tBlockCmt,
 	stateJSLineCmt:      tLineCmt,
 	stateJSHTMLOpenCmt:  tLineCmt,
@@ -270,7 +270,7 @@ func tURL(c context, s []byte) (context, int) {
 
 // tJS is the context transition function for the JS state.
 func tJS(c context, s []byte) (context, int) {
-	i := bytes.IndexAny(s, "\"`'/<-#")
+	i := bytes.IndexAny(s, "\"`'/{}<-#")
 	if i == -1 {
 		// Entire input is non string, comment, regexp tokens.
 		c.jsCtx = nextJSCtx(s, c.jsCtx)
@@ -283,7 +283,7 @@ func tJS(c context, s []byte) (context, int) {
 	case '\'':
 		c.state, c.jsCtx = stateJSSqStr, jsCtxRegexp
 	case '`':
-		c.state, c.jsCtx = stateJSBqStr, jsCtxRegexp
+		c.state, c.jsCtx = stateJSTmplLit, jsCtxRegexp
 	case '/':
 		switch {
 		case i+1 < len(s) && s[i+1] == '/':
@@ -320,12 +320,67 @@ func tJS(c context, s []byte) (context, int) {
 		if i+1 < len(s) && s[i+1] == '!' {
 			c.state, i = stateJSLineCmt, i+1
 		}
+	case '{':
+		c.jsBraceDepth++
+	case '}':
+		if c.jsTmplExprDepth == 0 {
+			return c, i + 1
+		}
+		for j := 0; j <= i; j++ {
+			switch s[j] {
+			case '\\':
+				j++
+			case '{':
+				c.jsBraceDepth++
+			case '}':
+				c.jsBraceDepth--
+			}
+		}
+		if c.jsBraceDepth >= 0 {
+			return c, i + 1
+		}
+		c.jsTmplExprDepth--
+		c.jsBraceDepth = 0
+		c.state = stateJSTmplLit
 	default:
 		panic("unreachable")
 	}
 	return c, i + 1
 }
 
+func tJSTmpl(c context, s []byte) (context, int) {
+	var k int
+	for {
+		i := k + bytes.IndexAny(s[k:], "`\\$")
+		if i < k {
+			break
+		}
+		switch s[i] {
+		case '\\':
+			i++
+			if i == len(s) {
+				return context{
+					state: stateError,
+					err:   errorf(ErrPartialEscape, nil, 0, "unfinished escape sequence in JS string: %q", s),
+				}, len(s)
+			}
+		case '$':
+			if len(s) >= i+2 && s[i+1] == '{' {
+				c.jsTmplExprDepth++
+				c.state = stateJS
+				return c, i + 2
+			}
+		case '`':
+			// end
+			c.state = stateJS
+			return c, i + 1
+		}
+		k = i + 1
+	}
+
+	return c, len(s)
+}
+
 // tJSDelimited is the context transition function for the JS string and regexp
 // states.
 func tJSDelimited(c context, s []byte) (context, int) {
@@ -333,8 +388,6 @@ func tJSDelimited(c context, s []byte) (context, int) {
 	switch c.state {
 	case stateJSSqStr:
 		specials = `\'`
-	case stateJSBqStr:
-		specials = "`\\"
 	case stateJSRegexp:
 		specials = `\/[]`
 	}