How to capitalize first letter of each word, like a 2-word city?

My JS woks well when the city has one word:

• cHIcaGO ==> Chicago

But when it's

• san diego ==> San diego

How do I make it become San Diego?

function convert_case() {
    document.profile_form.city.value =
        document.profile_form.city.value.substr(0,1).toUpperCase() + 
        document.profile_form.city.value.substr(1).toLowerCase();
}

There's a good answer here:

function toTitleCase(str) {
    return str.replace(/\w\S*/g, function(txt){
        return txt.charAt(0).toUpperCase() + txt.substr(1).toLowerCase();
    });
}

or in ES6:

var text = "foo bar loo zoo moo";
text = text.toLowerCase()
    .split(' ')
    .map((s) => s.charAt(0).toUpperCase() + s.substring(1))
    .join(' ');

You can use CSS:

p.capitalize {text-transform:capitalize;}

Update (JS Solution):

Based on Kamal Reddy's comment:

document.getElementById("myP").style.textTransform = "capitalize";

function convertCase(str) {
  var lower = String(str).toLowerCase();
  return lower.replace(/(^| )(\w)/g, function(x) {
    return x.toUpperCase();
  });
}

The JavaScript function:

String.prototype.capitalize = function(){
       return this.replace( /(^|\s)([a-z])/g , function(m,p1,p2){ return p1+p2.toUpperCase(); } );
      };

To use this function:

capitalizedString = someString.toLowerCase().capitalize();

Also, this would work on multiple words string.

To make sure the converted City name is injected into the database, lowercased and first letter capitalized, then you would need to use JavaScript before you send it over to server side. CSS simply styles, but the actual data would remain pre-styled. Take a look at this jsfiddle example and compare the alert message vs the styled output.