Property 'value' does not exist

let el:HTMLElement = document.getElementById('test') as HTMLElement;
if(el.value !== ''){
}

报错Property 'value' does not exist on type 'HTMLElement'

解决方案

let el:HTMLElement = document.getElementById('test')  as HTMLElement;
if((el as HTMLElement).value !== ''){
}

Property XXX does not exist on type 'HTMLElement' 问题同理解决