javascript validation issue for password

Question

im having some issues concerning my javascript code for password. here's my code .that part is working fine, but i want to put another condition where my password should contains at least 8 characters and must abide the following rules : no spaces, contains at least 1 Uppercase and a number. concerning the mobile, it must always start with the no. 5 . help <3

    function formValidation() {
 var mobile = document.forms["form"]["mobile"].value;
        var password = document.forms["form"]["password"].value;
       
//reg expression check
 var checkNumbers = /^[0-9 ]+$/;


$(document.forms["form"]["mobile"]).focus(function(){
		$(document.forms["form"]["mobile"]).css("background-color", "white");
	});
$(document.forms["form"]["password"]).focus(function(){
		$(document.forms["form"]["password"]).css("background-color", "white");
function clear(){
$(document.forms["form"]["mobile"]).focus(function(){
		$(document.forms["form"]["mobile"]).css("background-color", "white");
	});
$(document.forms["form"]["password"]).focus(function(){
		$(document.forms["form"]["password"]).css("background-color", "white");
	});
}

 if (mobile == null || mobile == "") {
        error[error.length]=("Enter your mobile number"); 
        document.form.mobile.focus();
        $(document.forms["form"]["mobile"]).css("background-color", "blue");  
        ;         
    }else if (mobile != null || mobile != "") {
    	if(!checkNumbers.test(mobile)){
    	error[error.length]=("Enter Only numeric Characters for mobile phone");
		document.form.mobile.focus();
		$(document.forms["form"]["mobile"]).css("background-color", "blue");
    	}
               
    }
        if (password == null || password == "") {
            error[error.length]=("Enter a password"); 
            document.form.password.focus();
            $(document.forms["form"]["password"]).css("background-color", "blue");   
        }

    }

   		
    <form name="form" onsubmit="return formValidation()" action="process.html">
    
Mobile phone:
		<input type="text" name="mobile" id="mobile"></br></br>

Password:
    <input type="password" name="password" id="password"></br></br>
    </form> 
<input id="submit" type="submit" name="submit" id="submit">

Answer 1

If you break it down into parts you can do this really easily and inform the user exactly which constraint they are failing, like this:

// Check the length:
if (password.length < 8) { // ... not long enough }

// Check if it has at least one upper case:
if (password.match(/[A-Z]+/g) === null) { // ... no upper case characters }

// Check if it has at least one number:
if (password.match(/\d/g) === null) { // ... no numbers }

// Password passes validation!