JavaScript code snippets used to convert text to uppercase and lowercase. This is a simple example to demonstrate changes to form input values. See: jQuery titleCaps function

 jQuery('form').submit(function() {
    jQuery('input#value').val(function(i, val) {
          return val.toUpperCase();
           return val.toLowerCase();
    });
});

FAQ for jQuery toUpperCase() and toLowerCase() methods (FAQ)

What is the difference between jQuery toUpperCase() and toLowerCase() methods?

jQuery's toUpperCase() and toLowerCase() methods are used to change the case of text in JavaScript. toUpperCase() method converts the string to uppercase letters, while toLowerCase() method converts the string to lowercase letters. These methods do not change the original string, but return a new string with the required case.

How to use the toLowerCase() method in jQuery?

Using toLowerCase() method in jQuery is very simple. You just need to call the method on the string you want to convert to lowercase. Here is an example:

 var str = "Hello World!";
var lowerCaseStr = str.toLowerCase();
console.log(lowerCaseStr); // Output: "hello world!"

In this example, the string "Hello World!" is converted to lowercase using toLowerCase() method.

Can I use the toUpperCase() method for numbers or special characters?

toUpperCase() method in jQuery only affects alphabetical characters. Numbers, special characters, and spaces are not affected by this method. If you call toUpperCase() on a string that contains only numbers or special characters, the original string is returned without any changes.

Are the toUpperCase() and toLowerCase() methods case sensitive?

No, toUpperCase() and toLowerCase() methods in jQuery are case-insensitive. They convert all alphabetical characters in the string to the desired case regardless of their original case.

Can I use the toUpperCase() and toLowerCase() methods with other jQuery methods?

Yes, you can link toUpperCase() and toLowerCase() methods with other jQuery methods. This is a common practice in jQuery that can make your code more concise and easy to read.

How to convert only the first letter of a string to uppercase?

To convert only the first letter of a string to uppercase in jQuery, you can use charAt() method and toUpperCase() method in combination. Here is an example:

 var str = "hello world!";
var firstLetterUpperCaseStr = str.charAt(0).toUpperCase() str.slice(1);
console.log(firstLetterUpperCaseStr); // Output: "Hello world!"

In this example, the first letter of the string "hello world!" is converted to capitalization.

What happens if I call the toLowerCase() method on an empty string?

If you call toLowerCase() method on an empty string in jQuery, it will return another empty string. toLowerCase() method does not change the original string, so calling it on an empty string will not produce any errors or unexpected results.

Can I use the toUpperCase() and toLowerCase() methods for non-string data types in jQuery?

toUpperCase() and toLowerCase() methods in jQuery are designed to handle strings. If you try to use these methods for non-string data types, you will receive TypeError . To avoid this, always make sure that the data you are processing is a string before calling these methods.

Are the toUpperCase() and toLowerCase() methods in jQuery supported in all browsers?

Yes, toUpperCase() and toLowerCase() methods are part of the JavaScript ECMAScript standard and are supported in all modern browsers including Chrome, Firefox, Safari, and Edge.

How to convert a string to title case in jQuery?

To convert a string to title case in jQuery, you can use toLowerCase() and toUpperCase() methods in combination with split() and join() methods. Here is an example:

 var str = "hello world!";
var titleCaseStr = str.toLowerCase().split(' ').map(function(word) {
  return word.charAt(0).toUpperCase() word.slice(1);
}).join(' ');
console.log(titleCaseStr); // Output: "Hello World!"

In this example, the string "hello world!" is converted to title case, which means that the first letter of each word is capitalized.

The above is the detailed content of jQuery toUpperCase/toLowerCase Example. For more information, please follow other related articles on the PHP Chinese website!