页面中禁用enter键

// 禁用enter键
    document.onkeydown = function(event) {
        var target, code, tag;
        if (!event) {
            event = window.event; //针对ie浏览器
            target = event.srcElement;
            code = event.keyCode;
            if (code == 13) {
                tag = target.tagName;
                if (tag == "TEXTAREA") { return true; }
                else { return false; }
            }
        }
        else {
            target = event.target; //针对遵循w3c标准的浏览器，如Firefox
            code = event.keyCode;
            if (code == 13) {
                tag = target.tagName;
                if (tag == "INPUT") { return false; }
                else { return true; }
            }
        }
    };