CODEWITHSUNDEEP
javascripthtml
Samuel Okike
Samuel Okike

Reputation: 13

I need to create a backspace function for my calculator with javascript

I'm programming a simple calculator with javascript, and I'm finding it hard to make a correct backspace function.

When the backspace button is clicked, I want it to remove the last character on the screen.

NB: I know I'm nowhere close to the correct solution, I'm a newbie, so go easy on me :D.

Here's my code:

// Clear and backspace  
            
            function clearAll() {
                if (control){
                    lastScreen = screenView.value;
                    screenView.value = 0;
                    alert("cleared!");
                }
            }
            
            function backSpace() {
                if (control) {
                    var newScreenView = [];
                    if (screenView.value != 0) {
                        screenViewLength = screenView.value.length;
                        for (i = 0; i < screenViewLength; i++) {
                            newScreenView.push(screenView.value[i]);
                        }
                        remove = newScreenView.length ;
                        console.log(newScreenView[remove]);
                        //screenView.value = newScreenView;
                    }
                
                alert("backspace");
                }
            }

<input type="button" id="backspace_button" onclick="backSpace()" value="<="/>

Upvotes: 1

Views: 6244

Answers (3)

Pavel Gatnar
Pavel Gatnar

Reputation: 4053

Simply use substr method: 

screenView.value = screenView.value.substr(0, screenView.value.length - 1)

But if you hold the user input in a buffer: 

buffer.pop()
screenView.value = buffer.join('')

Upvotes: 0

Mingle Li
Mingle Li

Reputation: 1350

function backSpace(){
    screenView.value = screenView.value.slice(0, - 1);
}

One liner right there!

Upvotes: 0

Alex Hill
Alex Hill

Reputation: 711

Just slice the string

screenView.value = screenView.value.slice(0, screenView.value.length -1)

Upvotes: 4

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