getIndexByValue is not defined

Sorry for my English(I dont learn in well yet)

When I try to use following code

    var index_cat=getIndexByValue("2");
    combo_category2.selectOption(index_cat);

I have error:

getIndexByValue is not defined

error source line: [Break on this error] var index_cat=getIndexByValue(“2”);

All other API method that I have use work properly %(

I has included this files

Where is my mistake?
Thank you!

I understood what went wrong.