Enter键禁止表单提交

//禁用Enter键表单自动提交
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) {
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) {
return false;
}
}
};