好像找到了，js/indexfunc.js

但要自己写函数，估计有点悬

TEXT TO jsCode TEXTMERGE NOSHOW PRETEXT 15
    var isFpdm = function(fpdm){
        var _0x2cbf61 = _0x1136c8;
        if (exec)
            return false;
        var _0x5906a4 = fpdm;
        if ('' === _0x5906a4)
            return false;
        if ((_0x5906a4[_0x2cbf61(0x183)] == 0xa || _0x5906a4['length'] == 0xc) && _0x5906a4[_0x2cbf61(0x19a)](',') === -0x1){
            return (typeof(afcdm(_0x5906a4))=="undefined");
        }
        $(_0x2cbf61(0x1d7))[_0x2cbf61(0x176)](_0x2cbf61(0x1a7));
        $('#fpdmjy')[_0x2cbf61(0x176)]('font_red');
        $(_0x2cbf61(0x1d7))[_0x2cbf61(0x1df)](_0x2cbf61(0x18b));
        acb(fplx);
        return false;
    };
ENDTEXT
这一段代码能不能简化一下，不要判断语句，只要最后的执行语句afcdm(_0x5906a4)，因为输入的代码、号码一定是正确的

我改成这样了，
TEXT TO jsCode TEXTMERGE NOSHOW PRETEXT 15
    var isFpdm = function(fpdm){
        var _0x5906a4 = fpdm;
        afcdm(_0x5906a4);
        return true;
    }
ENDTEXT
运行成功

挺好玩的，我又改了一下
TEXT TO jsCode TEXTMERGE NOSHOW PRETEXT 15
    var isFpdm = function(fpdm){
        afcdm(fpdm);
        return true
    }
ENDTEXT
也可以

好的
发票号码太麻烦了，看不懂了，找不到最后执行的是哪个函数，麻烦帮我看看吧

12345678就可以，8位数字

好像可以直接用)['keyup'](function()这个函数，因为在发票号码、和发票代码输入后都会调用这个函数

我又憨胆大，改成直接调用了
        bFpdm = thisform.wb.document.Script.afcdm(of.wb.Document.getElementByid("fpdm").value)
        bFpdm = thisform.wb.document.Script.ahmch(of.wb.Document.getElementByid("fphm").value)
达到效果了
完整代码
of = CREATEOBJECT("webForm")
of.show
READ EVENTS
RETURN

DEFINE CLASS webForm AS Form
    ShowWindow = 2
    WindowState = 2
    ADD OBJECT txt1 as textbox WITH left=10,top=10,width=130,height=22,value="051002000511"
    ADD OBJECT cmd1 as commandbutton WITH left=150,top=10,height=22,Enabled=0,caption="test"
    ADD OBJECT WB AS Olecontrol WITH left=0,top=42, Width=this.width,Height=this.height-42,Anchor=15,OleClass="Shell.Explorer.2",Visible=.T.
    PROCEDURE Destroy
        CLEAR EVENTS
    ENDPROC
    PROCEDURE Init
        this.WB.Silent = 0  &&提示安全证书问题警告
        this.WB.Navigate("https://inv-veri.chinatax.)
    ENDPROC
    PROCEDURE WB.documentComplete(pdisp, url)
        IF SYS(3095,pdisp)==SYS(3095,this)
            thisform.wb.Document.parentWindow.execScript(jsCode)
            thisform.cmd1.Enabled = 1
        ENDIF
    ENDPROC   
    PROCEDURE cmd1.click
        of.wb.Document.getElementByid("fpdm").value="051002000511"
        of.wb.Document.getElementByid("fphm").value="12345678"
        bFpdm = thisform.wb.document.Script.afcdm(of.wb.Document.getElementByid("fpdm").value)
        bFpdm = thisform.wb.document.Script.ahmch(of.wb.Document.getElementByid("fphm").value)
    ENDPROC
ENDDEFINE

谢谢，又学到了很多知识