How do you get the cursor position in a textarea?

Diving deep: cursor and selection properties

Expanding beyond selectionStart, the key to mastering cursor and selection manipulation in textareas lies in understanding its companion property selectionEnd. Available on the HTMLTextAreaElement, they form the twin towers of cursor handling.

Understanding selectionEnd

selectionEnd gives the end of a text selection:

const selectionEndPos = document.getElementById('myTextarea').selectionEnd;
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In cases of text selection, selectionStart and selectionEnd differ. When no text is selected, they are equal, representing the cursor position.

Crossing browser fences

For older browser support, consider sprinkling your code with a dedicated library or polyfill spice.

Ensuring textarea focus

Before extracting or setting the cursor position, confirm the textarea is in focus:

const textarea = document.getElementById('myTextarea');
textarea.focus(); // Just ensuring the textarea is 'awake'
const cursorPosition = textarea.selectionStart;
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A more refined approach

To add zest to your cursor manipulating recipe, use custom utility functions like getCursorPos and setCursorPos.

Making it reactive

React to user interactions by coupling cursor position changes with events like keyup, click, or focus. This keeps your application agile and ready.

Advanced cursor manipulation techniques

For a sublime user experience, enrich your application by placing the cursor at a specific location or discerning the cursor's line number.

Setting the cursor position

To serve cursor position on-demand:

const setCursorPos = (textarea, pos) => {
    textarea.selectionStart = pos;
    textarea.selectionEnd = pos;
}; // With this function, cursor positioning is a piece of cake.
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Tracking by line number

To find out the line number, dish out some cherry-picked metrics:

const getLineNumber = (textarea) => {
    // Code to calculate line number from the cursor position
}; // Remember, great challenges cook great code.
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Empowered by these function, you can transform text into lines and lines into wealth of positional data.

Catering to special cases

Thinking outside the box can help conquer challenges like dealing with wrapped text or determining the cursor's position relative to the overall window.

Handling wrapped text

Wrapped text presents an interesting case for the cursor positioning. A meticulously stirred code cocktail can overcome this irregular terrain.

Aligning to window coordinates

To find the cursor's x, y coordinates, convert the index position into pixel coordinates. This secret sauce may need shadow DOM magic for precise measurements.

Sizzling references

Keep a jsfiddle or CodePen grilling for quick testing and reference.

Visual representation

Still confused? Here's a visual to help you see it in action:

Textarea:
+---------------------------------+
| I am an explorer (😎) in the     |
| vast jungle of texts, seeking   |
| my current position...          |
+---------------------------------+
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Here's how you get the position:

document.getElementById('textarea').selectionStart;
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This provides the index where our 'explorer' (😎) is positioned.

Position: [😎] -> Index 16 (📍)
// Our 'emoji' explorer landed at index 16. What a journey!