let y12, y11, x12, x11, bv;
…………………………..
app.post('/init', (req, res) => {
    ({ y12, y11, x12, x11, bv } = req.body);
    console.log('После присваивания:', { y12, y11, x12, x11, bv });
      console.log(`y12 = ${y12}`);
       console.log(`y11 = ${y11}`);
       console.log(`x12 = ${x12}`);
       console.log(`x11 = ${x11}`);
       console.log(`xv = ${xv}`);
       console.log(`bv = ${bv}`);
});

function FFF(y12, y11, x12, x11, xv, bv) {
   if (y12 === undefined || y11 === undefined || x12 === undefined || x11 === undefined || bv === undefined) {
    // Code to execute if any variable is undefined
       console.log('После вызова FFF:', { y12, y11, x12, x11, xv, bv });
   } else {
       console.log(`y12 = ${y12}`);
       console.log(`y11 = ${y11}`);
       console.log(`x12 = ${x12}`);
       console.log(`x11 = ${x11}`);
       console.log(`xv = ${xv}`);
       console.log(`bv = ${bv}`);
    const deltaX = x12 - x11;
    const deltaY = y12 - y11;
    const m = deltaY / deltaX;
    const Uvel = (m * xv + bv);
    return parseFloat(Uvel.toFixed(1)); 
   }
}; 

$ node item.js
Server is running on port 3000
После присваивания: { y12: 12.3, y11: 4.02, x12: 3.03, x11: 0.9, bv: 0.526 }
y12 = 12.3
y11 = 4.02
x12 = 3.03
x11 = 0.9
xv = 0
bv = 0.526

y12 = 0.9
y11 = 3.03
x12 = 4.02
x11 = 12.3
xv = 1.911 это верно
bv = 0.526 это верно

Index.html имеет этот код

function uploadData() {
    const y12 = parseFloat(document.getElementById("U2").value);
    const y11 = parseFloat(document.getElementById("U1").value);
    const x12 = parseFloat(document.getElementById("n2").value);
    const x11 = parseFloat(document.getElementById("n1").value);
    const bv = parseFloat(document.getElementById("b").value);

    fetch('/init', {
        method: 'POST',
        headers: {
            'Content-Type': 'application/json'
        },
        body: JSON.stringify({ y12, y11, x12, x11, bv })
    })
    .then(response => response.json())
    .then(data => {
        console.log(data.array);
    })
    .catch(error => {
        console.error('Error:', error);
    });
}

item.js вот этот код

let y12, y11, x12, x11, bv;
……………...
app.post('/init', (req, res) => {
    //const { y12, y11, x12, x11, bv = req.body;
 console.log('Полный req.body:', req.body); // что приходит на сервер

    const y12 = req.body.y12;
    const y11 = req.body.y11;
    const x12 = req.body.x12;
    const x11 = req.body.x11;
    const bv = req.body.bv;

    console.log('После присваивания:', { y12, y11, x12, x11, bv });
});

$ node item.js
Server is running on port 3000
Полный req.body: { y12: 12.3, y11: 4.02, x12: 3.03, x11: 0.9, bv: 0.526 }
После присваивания: { y12: 12.3, y11: 4.02, x12: 3.03, x11: 0.9, bv: 0.526 }
One or more variables are undefined

(mapcar (lambda (chr) 
          (if (eql chr ?.) 
              ?. 
              (- chr ?0))) 
        "123.45")
;; => (1 2 3 46 4 5)  ; . is 46 in ASCII 

(map 'list '#(lambda (chr) 
          (if (eql chr ?.) 
              ?. 
              (- chr ?0))) 
        "123.45")
;; => попробовать не могу сейчас(1 2 3 46 4 5)  ; . is 46 in ASCII 

in r18, 0x04
in r19, 0x05

avr-gcc -mmcu=atmega8 -nostartfiles -Wl,--undefined=_mmcu blink.s -o blink.elf

vr-objdump -h blink.elf

.equ DDRB = 0x37  ;ОШИБКА

;;; Blinks LED on PB0 (pin 14) using a simple delay loop.
; blink.s — AVR GAS syntax for avr-gcc

; Symbol definitions (note the comma in .equ)
.equ DDRB,  0x37          ; I/O address of DDRB for ATmega8
.equ PORTB, 0x38          ; I/O address of PORTB
.equ PB0,   0             ; bit number 0

.org 0x0000
rjmp reset                 ; reset vector

reset:
    ldi  r16, (1 << PB0)   ; PB0 is a plain constant
    out  DDRB, r16         ; set PB0 as output

loop:
    ldi r16, (1<<PB0)      ; PB0 high
    out PORTB, r16
    rcall DELAY

    ldi r16, (0<<PB0)      ; PB0 low
    out PORTB, r16
    rcall DELAY
    rjmp loop

DELAY:
    ldi r17, 200
D1: dec r17
    brne D1
    ldi r18, 255
D2: dec r18
    brne D2
	ret

	/* Define the .mmcu section for simavr */
.section .mmcu,"a",@progbits

/* VCD Trace Header: tells simavr to create 'trace.vcd' */
.byte 0x01          /* tag for AVR_MMCU_TAG_VCD_TRACE */
.byte 24            /* size of this chunk */
.asciz "trace.vcd"  /* filename */

/* Trace entry: Monitor PORTB (Address 0x38 for ATmega8) */
.byte 0x02          /* tag for a trace symbol */
.byte 8             /* size */
.byte 0x38          /* address of PORTB in ATmega8 */
.byte 0x01          /* mask (bit 0) */
.asciz "LED_PIN"    /* name of the trace in GTKWave */

.byte 0x00          /* End of section */
	

bash
avr-gcc -mmcu=atmega328p -x assembler-with-cpp -Wa,-gstabs \
  -c main.S -o main.o

Notes:

    -mmcu=... selects the same device as in AVR Studio’s project settings.

    -x assembler-with-cpp lets you use #define, #include, etc., through the C preprocessor (Studio often did that behind the scenes).

    -Wa,options passes options to the assembler; -gstabs or -g lets you debug in GDB/simulavr similarly to Studio’s debug info.

bash
avr-gcc -mmcu=atmega328p -x assembler -c main.S -o main.o

bash
avr-gcc -mmcu=atmega328p -Wl,-Map=project.map \
  main.o other.o -o project.elf

bash
avr-gcc -mmcu=atmega328p -nostartfiles -nostdlib \
  -Wl,-Map=project.map,-Tyour_linker_script.ld \
  main.o -o project.elf

bash
avr-objcopy -O ihex -R .eeprom project.elf project.hex

avr-objcopy -O ihex -j .eeprom --set-section-flags .eeprom=alloc,load \
  --change-section-lma .eeprom=0 \
  project.elf project_eeprom.hex

avr-size -C --mcu=atmega328p project.elf

MCU = atmega328p
CC  = avr-gcc
OBJCOPY = avr-objcopy
SIZE = avr-size

ASFLAGS = -mmcu=$(MCU) -x assembler-with-cpp -Wa,-gstabs
LDFLAGS = -mmcu=$(MCU) -Wl,-Map=project.map

all: project.hex

project.elf: main.o
	$(CC) $(LDFLAGS) $^ -o $@

%.o: %.S
	$(CC) $(ASFLAGS) -c $< -o $@

project.hex: project.elf
	$(OBJCOPY) -O ihex -R .eeprom $< $@
	$(SIZE) -C --mcu=$(MCU) $<

<select id="list"></select>
<script>console.dir(document.querySelector('#list').__proto__)</script>

javascript
const selectElement = document.querySelector('#list');
const selectedValue = selectElement.value; // Получаем значение выбранного элемента
const selectedIndex = selectElement.selectedIndex; // Получаем индекс выбранного элемента

console.log(`Выбранное значение: ${selectedValue}, Индекс: ${selectedIndex}`);

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatable" content="ie=edge">
    <title>Document</title>
</head>
  <body>
    <style>
      table, tr, td{
	  border: 1px solid;
  border-collapse: collapse;
}
      </style>
    <table id="myTable">
      <tr>
	<td>string</td>
	<td>4</td>	
      </tr>
            <tr>
	<td>string</td>
	<td>4</td>	
	    </tr>
	          <tr>
	<td>string</td>
	<td>4</td>	
		  </tr>
		        <tr>
	<td>string</td>
	<td>10</td>	
			</tr>
			      <tr>
	<td>string</td>
	<td>12</td>	
      </tr>
	      <tr>
	<td>string</td>
	<td>4</td>	
	      </tr>
	            <tr>
	<td>string</td>
	<td>4</td>	
      </tr>
      </table>
<button onclick="myFunction()">Try it</button>

<script>
function myFunction() {
  alert(document.getElementById("myTable").rows[2].cells[1].innerHTML);
}
</script>
  </body>
</html>

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatable" content="ie=edge">
    <title>Document</title>
</head>
<html>
<head>
<style>
   table,
   td {
      border: 1px solid black;
   }
</style>
</head>
<body>
<table id="position1">
  <tr>
    <td onclick="runM(this)">TL</td>
    <td onclick="runM(this)">TC</td>
    <td onclick="runM(this)">TR</td>
  </tr>  
</table>
<script>
     function runM(txt){
	 console.log(txt.cellIndex);
     }
</script>
</body>
</html>