jsc-1: command not found

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

If it's empty, You may set the PATH variable with this command

export PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin"

On CentOS possible default full paths are:

/usr/bin/jsc-1 - from package: webkitgtk-devel

You may install the required package with command yum install {package}

Error in other languages:
jsc-1: bevel nie gevind nie
jsc-1: comandă negăsită
jsc-1: comando não encontrado
jsc-1: commande introuvable
jsc-1: command not found
jsc-1: käsku ei ole
jsc-1: không tìm thấy lệnh
jsc-1: komanda nerasta
jsc-1: Kommando nicht gefunden.
jsc-1: kommandot finns inte
jsc-1: komut yok
jsc-1: nie znaleziono polecenia
jsc-1: níor aimsíodh an t-ordú
jsc-1: no se encontró la orden
jsc-1: no s'ha trobat l'ordre
jsc-1: opdracht niet gevonden
jsc-1: parancs nem található
jsc-1: perintah tidak ditemukan
jsc-1: príkaz nenájdený
jsc-1: příkaz nenalezen
jsc-1: команда не найдена
jsc-1: командата не е открита
jsc-1: 命令找不到
jsc-1: コマンドが見つかりません