index.js

let screen=document.getElementById('screen');
buttons=document.querySelectorAll('button');
let screenValue=' ';
for(item of buttons){
    item.addEventListener('click',(e)=>{
        buttonText=e.target.innerText;
        console.log('Button text is ',buttonText);
        if(buttonText=='✕'){
            buttonText='*';
            screenValue+=buttonText;
            screen.value=screenValue;
        }
        else if(buttonText=='C'){
            screenValue=" ";
            screen.value=screenValue;
        }
        else if(buttonText=='='){
            screen.value=eval(screenValue);
        }
        else{
            screenValue+=buttonText;
            screen.value=screenValue;
        }
    })
}