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cs2 Discord

View scripts

ClientScript2 (cs2) is a client-side scripting language used in Old School RuneScape to dynamically update interfaces. Players load scripts from the game cache in a custom bytecode format to be interpreted by the client.


There are two main kinds of scripts:

ClientScript: Added as callbacks for actions such as user interactions with interface components. When the user performs the action, such as click or mouse-leave, the script is executed. Cannot return any values.

Procedure: can only be called inside of another script. The caller may be of either kind. Able to both take arguments and return values.


The first line of a script is its signature. It contains the script's kind, name, the types and names of its parameters, and its return types. A script may return multiple values. A Procedure is indicated by proc and a ClientScript by clientscript.

[proc,min](int $a, int $b)(int)

[clientscript,settrans](component $component, int $trans)

Each script can take a maximum of 50 arguments and return a maximum of 50 values. If a script does not return anything, the parentheses around its return types can be omitted.


Global variables: Defined outside of scripts in config files. Can be used and modified inside any script. Accessed by prefixing its name with a percent sign, like %raids_lobby_partysize. Internally stored as either varps, varbits, or varcs.

Global constants: Unable to be modified. Defined outside of scripts. Accessed by prefixing its name with a caret, like ^iftype_rectangle.

Local variables: Must be defined and initialized to a valid value before being used. Only accessible inside the script in which it is defined. Accessed by prefixing its name with a dollar sign, like $scrollbar. Arguments are also local variables which are initialized to the passed in values.


null is a valid value for all types except for string

  • int : a 32-bit signed integer. Written normally or as a hexadecimal literal. null is equivalent to -1
    • 5, -10, 0x7f7f7f
  • string : a sequence of characters, can be empty. Written enclosed in quotes. String interpolation can be performed by enclosing a string typed expression in angle brackets and embedding it in a string literal.
    • "Show", "Magic level: <tostring($lvl)>"
  • boolean :
    • true, false
  • coord : a tile. Written as 5 numbers separated by underscores: the plane, the coordinates of the map-square, then the coordinates inside of the map-square
    • 0_1_2_3_4
  • component an interface component. Written as the interface, a colon, then the component
    • poh_jewellery_box:frame
  • obj : an item
  • namedobj : an item explicitly specified in the code. Can be used as an obj
    • lawrune
  • enum
  • stat : a skill.
    • attack, smithing
  • graphic : a sprite. Written with its name enclosed in quotes
    • "magicoff,12"
  • inv : an inventory of items such as the player's inventory or the bank
  • model
  • category
  • loc
  • area
  • maparea
  • fontmetrics : a font
    • p11_full
  • char
  • struct
  • synth
  • mapelement
  • npc
  • seq


Are a fixed length and all elements must be the same type. Can be of any type except for string. Max length of 5000. int elements are initialized to 0, all other types to null. Max of 5 arrays per script. Scripts may take only 1 array argument. Arrays can only be local variables and never globals.

Defining $array as an int array of length $len : def_int $array($len);

Getting the $ith element of $array : $array($i)

Setting the $ith element of $array to $n : $array($i) = $n;

Control Flow

The only things which can be used in the test condition of an if or while statement are the following operators:

  • Equality comparisons
    • = : equals
    • ! : not equals
  • Relational comparisons
    • < > <= >=
  • Short circuiting logical operators
    • & : AND
    • | : OR

Combinations of these operators may also be used. Variables or other expressions of type boolean may not be used on their own or as arguments to the logical operators. These operators cannot be used outside of an if or while statement.

Using an if statement to clamp an int value between $max and $min

if ($n > $max) {
} else if ($n < $min) {
} else {

Using a while statement to repeat something 10 times

def_int $i = 0;
while ($i < 10) {
    // ...
    $i = calc($i + 1);

There is no continue or break functionality.


Any expression that is not of type string can be the target of a switch statement. The cases must be constants. Multiple cases may lead to the same block. There is no fall-through between blocks. An optional default case can be used if none of the other cases are matched.


// Indicates the start of a line comment and all following text up until the end of the line is ignored


Most instructions are indicated by their name followed by a list of their arguments, sound_synth(2266, 1, 0). If it takes no arguments the parentheses can be omitted, clan_leavechat.

A Procedure is called by using a tilde followed by its name and arguments, ~min($a, $b). If it takes no arguments the parentheses can be omitted, ~wilderness_level.

Math on int expressions is performed using the calc instruction. It supports the infix operators + (addition), - (subtraction), / (division), * (multiplication), % (modulus), | (bitwise OR), & (bitwise AND). Precedence can be established using parentheses. The entire mathematical operation is passed as an argument to calc and the result is returned. def_int $c = calc($a * $b + 2);

An instruction which returns multiple values can be used either directly as multiple arguments to another instruction or assigned to multiple variables, $int2, $int3 = ~poh_jewellerybox_getbuttonspacing(590:2, 3);


A ClientScript can be assigned as a reoccurring callback for an action by using one of the instructions which start with either if_seton or cc_seton. They take as their first argument the name of the ClientScript and its arguments all enclosed in quotes. The ClientScript is not executed immediately but instead executed with the given parameters each time the action occurs.

cc_setonmouseover("autocast_tooltip($component1, $obj5)");

Instead of using existing variables as arguments, special values starting with event_ can be used which are resolved at the time the action occurs. If a mouse event is being used event_mousex will be replaced by the mouse's x position when the event is triggered.

cc_setondrag("scrollbar_vertical_drag($component0, $component1, event_mousey, false)");

ClientScripts can not only be assigned to interface actions but also to changes in varps, skills, or inventories. In this case the values which should be watched are added in braces after the arguments.

if_setonvartransmit("deadman_tournament_hudupdate(){var1542, var1293}", 90:11);