https://developers.google.cn/web/fundamentals/design-and-ux/input/forms/
Constraint Validation API https://dev.w3.org/html5/spec-preview/constraints.html#constraint-validation
Constraint Validation API(MDN) https://developer.mozilla.org/zh-CN/docs/Web/Guide/HTML/HTML5/Constraint_validation
<body>
<!--[if lt IE 8]> <h3>请升级你的浏览器，或更换主浏览器！！!</h3> <![endif]-->
<form>
<input id=text1 type=text required minlength=10 />
<input id=submit1 type=submit>
</form>
<script>
document.querySelector('#submit1')
.addEventListener('click',function(){
var text1 = document.querySelector('#text1');
console.log( text1.validationMessage);
if( text1.checkValidity() ){
text1.setCustomValidity('good')
}else{
text1.setCustomValidity('')
}
},false);
</script>
</body>