String() 函数把对象的值转换为字符串。

var test1 = new Boolean(1);
var test2 = new Boolean(0);
var test3 = new Boolean(true);
var test4 = new Boolean(false);
var test5 = new Date();
var test6 = new String("999");
var test7 = 12345;

document.write("var test1 = new Boolean(1);    转为字符串：" + String(test1) + "<br />");
document.write("var test2 = new Boolean(0);    转为字符串：" + String(test2) + "<br />");
document.write("var test3 = new Boolean(true);转为字符串：" + String(test3) + "<br />");
document.write("var test4 = new Boolean(false);转为字符串：" + String(test4) + "<br />");
document.write("var test5 = new Date();           转为字符串：" + String(test5) + "<br />");
document.write("var test6 = new String('999');  转为字符串：" + String(test6) + "<br />");
document.write("var test7 = 12345;                  转为字符串：" + String(test7) + "<br />");