在jQuery中使用.keyup计算字符的简单方法

Question

<input type="text" />

如何在JavaScript / jQuery中编写.keyup input的字符数？

Answer 1

$('input').keyup(function() {
    console.log(this.value.length);
});

keyup is a shortcut method for bind('keyup') .
And as of jQuery version 1.7, all of the above are deprecated we are encourage to use the on method to bind events, meaning that the code should look like this:

$('input').on('keyup', function() {
    console.log(this.value.length);
});

Answer 2

Example - This will alert out the number of characters

$('#textBoxId').bind('keyup', function(e){

     alert($(this).val().length);

});

This obviously assumes that the text box has an id of textBoxId. Otherwise change selector iof don't want to give it an id for some reason