使textarea支持tab缩进

//textarea支持tab缩进 $("textarea").on( 'keydown', function(e) { if (e.keyCode == 9) { e.preventDefault(); var indent = ' '; var start = this.selectionStart; var end = this.selectionEnd; var selected = window.getSelection().toString(); selected = indent + selected.replace(/\n/g, '\n' + indent); this.value = this.value.substring(0, start) + selected + this.value.substring(end); this.setSelectionRange(start + indent.length, start + selected.length); } })