regex numbers and letters but no space code example

Example 1: regex only letters not spaces

var re = /^[A-Za-z]+$/;

Example 2: regex for letters and spaces

/* Note this works with the onkeyup function in html with js */

function lettersandSpacesOnly(input){
    var regexs = /[^a-z ]*$/gmi;
    input.value = input.value.replace(regexs, "");
  }