问输入数字接受尾部短划线

EN

function validate(evt) {
  l = document.getElementsByTagName('input')[0].value.length;
  if(l === 0 && String.fromCharCode(evt.keyCode) === '-') return
  var theEvent = evt || window.event;
  var key = theEvent.keyCode || theEvent.which;
  key = String.fromCharCode( key );
  var regex = /[0-9]|\./;
  if( !regex.test(key) ) {
    theEvent.returnValue = false;
    if(theEvent.preventDefault) theEvent.preventDefault();
  }
}

<input type='text' onkeypress='validate(event)' />

<input name="Number" type="number" pattern="[0-9]*">

var numInput = document.querySelector('input');

// Listen for input event on numInput.
numInput.addEventListener('input', function(){
    // Let's match only digits.
    var num = this.value.match(/^\d+$/);
    if (num === null) {
        // If we have no match, value will be empty.
        this.value = "";
    }
}, false)



<input name="Number" type="number" min="0" >