Select all contents of a textbox when it receives focus (Vanilla JS or jQuery)

Run JavaScript after the DOM has loaded

Ensure your JavaScript runs after the DOM is fully loaded by encapsulating your script in a DOMContentLoaded event:

// Codesy waiting patiently for the DOM tree to grow
document.addEventListener('DOMContentLoaded', function() {   
  document.querySelector('input[type="text"]').addEventListener('focus', function(e) {
    e.target.select(); // Oh look, I found a focus event! Quick, select all the text!
  });
});


For jQuery, use the $(document).ready() shorthand:

// Knock-knock, the DOM is fully loaded. Ready to party!
$(function() {
  $('input[type="text"]').focus(function() { 
    $(this).select(); // Spotlight's on textbox! Ta-da! All the text!
  });
});


The event handlers in either case are tied post-DOM-load, averting premature execution.

Keep selection on click events

In cases where users click into the text field and somehow deselect the text, prepare an event listener for mouseup to prevent this behaviour:

document.querySelector('input[type="text"]').addEventListener('focus', function(e) {
  e.target.select();
  e.preventDefault(); // Nope, no deselection on my watch!
}, true);


And for jQuery:

$('input[type="text"]').on({
  mouseup: function(e) {
    e.preventDefault(); // Nuh-uh! Keep that text selected!
  },
  focus: function () { 
    $(this).select(); // Shine the limelight on our dear text!
  }
});


Both methods will ensure the text remains selected upon unintentional clicks after gaining focus.

The truce between Vanilla JS and jQuery

This solution works well for both Vanilla JS and jQuery environments, ensures optimal workflow, coexists peacefully with existing textbox functionalities, and is easy to maintain and integrate.

User experience enhancement strategies

Handling the mouseup event

To thwart accidental text deselection upon mouse button release:

document.querySelector('input[type="text"]').addEventListener('mouseup', function(e) {
  e.preventDefault(); // Maintaining text selection in style 
});


Cross-browser compatibility

Ensure your solution is in good terms with different browsers to ace user experience. Remember, a thorough cross-browser test is as needed as milk for cereals.

Adaptation to various textbox types

The code above focuses on type="text". Don't forget to consider other types like textarea or content-editable elements. Tailor your requirements as needed:

// Flexibility is key when you have all kinds of textboxes to cater to 
document.querySelectorAll('input[type="text"], textarea, [contenteditable="true"]').forEach(el => {
  el.addEventListener('focus', e => e.target.select());
});


Maximizing interaction efficiency

The automatic selection on focus means users can start editing without extra steps, similar to buying pre-peeled oranges - efficiency at its finest. Plus, the simplicity of the solution’s design facilitates easy maintenance, much like a self-cleaning oven.