Javascript replace special chars with empty strings

Ok, I have these string prototypes to work with, however, I don't understand what they do exactly.

String.prototype.php_htmlspecialchars = function()
{
 return this.replace(/&/g, '&amp;').replace(/</g, '&lt;').replace(/>/g, '&gt;').replace(/"/g, '&quot;');
}

String.prototype.php_unhtmlspecialchars = f开发者_开发知识库unction()
{
 return this.replace(/&quot;/g, '"').replace(/&gt;/g, '>').replace(/&lt;/g, '<').replace(/&amp;/g, '&');
}

String.prototype.php_addslashes = function()
{
 return this.replace(/\\/g, '\\\\').replace(/'/g, '\\\'');
}

String.prototype._replaceEntities = function(sInput, sDummy, sNum)
{
 return String.fromCharCode(parseInt(sNum));
}

String.prototype.removeEntities = function()
{
 return this.replace(/&(amp;)?#(\d+);/g, this._replaceEntities);
}

String.prototype.easyReplace = function (oReplacements)
{
 var sResult = this;
 for (var sSearch in oReplacements)
  sResult = sResult.replace(new RegExp('%' + sSearch + '%', 'g'), oReplacements[sSearch]);

 return sResult;
}

Basically, what I need to do is replace all instances of double quotes ("), >, <, single quotes ('), etc. etc.. Basically the same stuff that htmlentities() in php changes, but I need to replace them with an empty string, so that they are removed from the text.

Can I use any of the functions above? If not, how can I accomplish this in Javascript? Can I use a replace on the string?

Please, someone, help me here. I am placing this text into a select box and will be inputted into the database upon submitting of the form. Though, I am using PHP to remove all of these characters, however, I'm having difficulty finding a way to do this in Javascript.

Thanks :)

---

Remove special characters (like !, >, ?, ., # etc.,) from a string using JavaScript:

var temp = new String('This is a te!!!!st st>ring... So??? What...');
document.write(temp + '<br>');
temp =  temp.replace(/[^a-zA-Z 0-9]+/g,'');
document.write(temp + '<br>');

jsFiddle

Edit:

If you don't want to remove dot(.) from string:

temp =  temp.replace(/[^a-zA-Z 0-9.]+/g,'');