问如果...else if javascript

EN

var reValue = /^\s*$/;      
var phoneClass = /(^|\s)phoneValidate(\s|$)/;              
var phoneValue = 
     /^[01]?[- .]?(\([2-9]\d{2}\)|[2-9]\d{2})[- .]?\d{3}[- .]?\d{4}$/;  

for (var i=0; i < iLen; i++) {
    el = allElements[i];

    if(phoneClass.test(el.className) && reValue.test(el.value)){
        // The field is empty.
        aMessages += 'Please enter a phone number in: '+ el.name +'.\n';
    }
    else if (phoneClass.test(el.className) && phoneValue.test(el.value)) {
        // The field is not a valid phone number
        // Advise user to fix it
        aMessages += 'Please enter a valid phone number in: '+ el.name +'.\n';
    }
}