Support Tabs in Textareas

Submitted by:J Kamy81

Date added:07 September, 2019

Category:JavaScript

Normally the tab key moves to the next focusable thing. This inserts a tab character in instead.

Tags: tabs , textareas

Code Snippet:

HTMLTextAreaElement.prototype.getCaretPosition = function () { //return the caret position of the textarea
return this.selectionStart;
};
HTMLTextAreaElement.prototype.setCaretPosition = function (position) { //change the caret position of the textarea
this.selectionStart = position;
this.selectionEnd = position;
this.focus();
};
HTMLTextAreaElement.prototype.hasSelection = function () { //if the textarea has selection then return true
if (this.selectionStart == this.selectionEnd) {
return false;
} else {
return true;
}
};
HTMLTextAreaElement.prototype.getSelectedText = function () { //return the selection text
return this.value.substring(this.selectionStart, this.selectionEnd);
};
HTMLTextAreaElement.prototype.setSelection = function (start, end) { //change the selection area of the textarea
this.selectionStart = start;
this.selectionEnd = end;
this.focus();
};

var textarea = document.getElementsByTagName('textarea')[0];

textarea.onkeydown = function(event) {

//support tab on textarea
if (event.keyCode == 9) { //tab was pressed
var newCaretPosition;
newCaretPosition = textarea.getCaretPosition() + " ".length;
textarea.value = textarea.value.substring(0, textarea.getCaretPosition()) + " " + textarea.value.substring(textarea.getCaretPosition(), textarea.value.length);
textarea.setCaretPosition(newCaretPosition);
return false;
}
if(event.keyCode == 8){ //backspace
if (textarea.value.substring(textarea.getCaretPosition() - 4, textarea.getCaretPosition()) == " ") { //it's a tab space
var newCaretPosition;
newCaretPosition = textarea.getCaretPosition() - 3;
textarea.value = textarea.value.substring(0, textarea.getCaretPosition() - 3) + textarea.value.substring(textarea.getCaretPosition(), textarea.value.length);
textarea.setCaretPosition(newCaretPosition);
}
}
if(event.keyCode == 37){ //left arrow
var newCaretPosition;
if (textarea.value.substring(textarea.getCaretPosition() - 4, textarea.getCaretPosition()) == " ") { //it's a tab space
newCaretPosition = textarea.getCaretPosition() - 3;
textarea.setCaretPosition(newCaretPosition);
}
}
if(event.keyCode == 39){ //right arrow
var newCaretPosition;
if (textarea.value.substring(textarea.getCaretPosition() + 4, textarea.getCaretPosition()) == " ") { //it's a tab space
newCaretPosition = textarea.getCaretPosition() + 3;
textarea.setCaretPosition(newCaretPosition);
}
}
}
 
 

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