function isValidURL(url){
    var RegExp = /^(([\w]+:)?\/\/)?(([\d\w]|%[a-fA-f\d]{2,2})+(:([\d\w]|%[a-fA-f\d]{2,2})+)?@)?([\d\w][-\d\w]{0,253}[\d\w]\.)+[\w]{2,4}(:[\d]+)?(\/([-+_~.\d\w]|%[a-fA-f\d]{2,2})*)*(\?(&?([-+_~.\d\w]|%[a-fA-f\d]{2,2})=?)*)?(#([-+_~.\d\w]|%[a-fA-f\d]{2,2})*)?$/;
    if(RegExp.test(url)){
        return true;
    }else{
        return false;
    }
}

function checkField(){
    var frm = document.form, error = "";
	if(frm.nome.value == ""){
        error += "O campo nome precisa ser preenchido.\n";
    }
    if(!isValidURL(frm.url.value)){
        error += "Informe corretamente o link do vídeo.\n";
    }
    if(error != ""){
        alert(error);
        return false;
    }else{
        return true;
    }
}

///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////