如何使用JavaScript将所有用户输入转换为大写字母？

Question

I have a JavaScript function that checks the user input and will compare it against the database.

function checkUserInput() {
    var userInput = document.getElementById("textInput").value;
    var stringToCheckAgainst = random_images_array[num].split('.');

    if (userInput == stringToCheckAgainst[0]) {

        document.getElementById("row1").innerHTML = "<p>" + txt.fontsize(5) + "</p>";
        document.close();

    } else {
        //user has inputted an incorrect string
        document.getElementById("row1").innerHTML = "<p>" + txt1.fontsize(5) + "</p>";
        document.close();
    }
}

My problem is at the moment this function is case sensitive which means if the user types in “apple” it will return false statements as a fact that all of my objects are named with uppercase letters. How can I make my function not case sensitive to works with both lower case and uppercase letters no matter how the user is typing in?

Answer 1

您可以这样使用：

if (userInput.toUpperCase() == stringToCheckAgainst[0].toUpperCase()) {

Answer 2

Try this:

if(cmp_first.toUpperCase()===cmp_second.toUpperCase()){
    alert('Strings are Identical');
}else{
    alert('String mismatch');
}

Answer 3

var userInput = document.getElementById("textInput").value;
document.write(userInput.toUpperCase());

To convert a string to lowercase or uppercase letters, use: toLowerCase() and toUpperCase() methods.

var userInput = document.getElementById("textInput").value;
userInput.toLowerCase() // lowercase
userInput.toUpperCase() // UPPERCASE

Answer 4

-Use the toUpperCase() function.

Desired_string.toUpperCase