Even if youre new to the forum you can read right? There is literally a sub-forum right under this one called "Scripting" and under it "Scripting Help". Did you even look through the forum before posting? But whatever..
You need to make a is_blank function before using it since it doesnt exist, something like this should work.
PHP Code:
bool:is_blank(szString[]){
return szString[0]==EOS ? true : false;
}