Template language
It is an extremely simple one. If you are familiar with php take a look at libs/expand.php (120 lines of code). It consists of:
A number of predefined variables:
${webimroot}, ${jsver}, ${tplroot}, ${styleid}, ${pagination}, ${errors}
Access to localized messages:
${msg:<idofstring>}, example ${msg:typing.remote}
Access to variables passed to the page from the PHP code:
${page:<idofvar>}, example: ${page:predefinedAnswers}
Access to form variables (to have proper initial values):
<input .... value="${form:email}"/>
Include other .tpl file:
${include:chat.tpl}
Conditional clauses:
${if:varname} ${endif:varname}
${ifnot:varname} ${endif:varname}
${if:varname} ${else:varname} ${endif:varname}
(available variables: user, agent, historyParams, canChangeName, canpost, sslLink, neediframesrc, errors)
Editing/testing .tpl
Use "Settings -> Themes preview" page to check your templates in test environment.