SOURCE

function isOK(s){
    var REG = /^[\s\S]*.*[^\s][\s\S]{1,5}\s*$/;
    var REG1 = /^\s*[\s\S]{1,5}\s*$/;
    var REG3 = /^(?!(\s+$)){1,500}$/;
    
    var REG2 = /^[\u4e00-\u9fa5_a-zA-Z0-9_]{1,500}$/;


    return REG3.test(s);
}

var OO = '11';
console.log(isOK(OO));