int selectionStart

Source 

@DomName('HTMLInputElement.selectionStart')
@DocsEditable()
int get selectionStart =>
    _blink.BlinkHTMLInputElement.instance.selectionStart_Getter_(this);
void selectionStart=(int value)

Source 

@DomName('HTMLInputElement.selectionStart')
@DocsEditable()
set selectionStart(int value) =>
    _blink.BlinkHTMLInputElement.instance.selectionStart_Setter_(this, value);