HTML转义字符，HTML字符实体< &gt: &

/**
* @function escapeHTML 转义html脚本 < > & " '
* @param a  字符串
*/

function escapeHTML(a){
a = "" + a;
return a..replace(/&/g, "&").replace(/</g, "<").replace(/>/g, ">").replace(/"/g, """).replace(/'/g, "'");
}

/**
* @function unescapeHTML 还原html脚本 < > & " '
* @param a  字符串
*/
function unescapeHTML(a){
a = "" + a;
return a.replace(/</g, "<").replace(/>/g, ">").replace(/&/g, "&").replace(/"/g, '"').replace(/'/g, "'");
}