How to pass just a variable (not a struct member) into text/html template. Golang

Yes just use the dot in front of it:

http://play.golang.org/p/7NXu9SDiik

package main

import (
    "html/template"
    "log"
    "os"
)

var tmplString = `    // content of index.html
    {{define "index"}}
    {{.var1}} is equal to {{.var2}}
    {{end}}
`

func main() {
    tmpl, err := template.New("test").Parse(tmplString)
    if err != nil {
        log.Fatal(err)
    }
    varmap := map[string]interface{}{
        "var1": "value",
        "var2": 100,
    }
    tmpl.ExecuteTemplate(os.Stdout, "index", varmap)

}

It is possible to pass just a simple value of any type. If you do so, you can refer to it in the template as {{.}}.

Here is an example (try it on the Go Playgound):

s := "<html><body>Value passed: {{.}}</body></html>\n"

tmpl := template.Must(template.New("test").Parse(s))

tmpl.Execute(os.Stdout, false)
tmpl.Execute(os.Stdout, 1)
tmpl.Execute(os.Stdout, "me")

Output:

<html><body>Value passed: false</body></html>
<html><body>Value passed: 1</body></html>
<html><body>Value passed: me</body></html>