Add Tab support within a text area. In particular Metlifes Synapse site

textarea-tab.js

//Added tab support to Metlife Synapse json resume builder site 
$('#json_textarea').on('keydown', function(event){
	$this = $(this);
	var TAB_SPACES = 2;

	var getSpaces = function(){
		
		var space='';
		for(var i=0; i<TAB_SPACES; i++){
			space += ' ';
		}
		return space;
	}

	if (event.keyCode === 9){
	  	event.preventDefault();

	  	var start = $this.get(0).selectionStart
	  	  , end = $this.get(0).selectionEnd
	  	  , isShiftTab = false
	  	  , beginText = $this.val().substring(0, start)
	  	  , endText = $this.val().substring(end)
	  	  , spaces = getSpaces();

	  	if (event.shiftKey === true && beginText.substr(beginText.length - TAB_SPACES) === spaces) {
	  		beginText = $this.val().substring(0, start - TAB_SPACES);
	  		isShiftTab = true;
		}
		else{
			beginText += spaces;
		}

		$this.val(beginText + endText);

	  	$this.get(0).selectionStart = 
   		$this.get(0).selectionEnd = start + (isShiftTab ? -TAB_SPACES : TAB_SPACES);
    }

});