<style>
.amount_tendered {
text-align: right;
font-size: 24px;
width: 200px;
}
</style>
<form>
<input class="amount_tendered" id="text" type="number" min="0" value="0.00" onkeyup="formatNum(this);" onclick="this.select(); activated();">
</form>
<script type="text/javascript">
String.prototype.splice = function(idx, rem, str) {
return this.slice(0, idx) + str + this.slice(idx + Math.abs(rem));
};
function formatNum(obj){
var str = obj.value;
switch (true){
case str.length==1:
str = '0.0' + str;
break;
case str.length==3:
str = '0' + str;
}
var indices = [];
for(var i=0; i<str.length;i++) {
if (str[i] === "." && (str.length - i)!=3) indices.push(i);
}
for(var i=0; i<indices.length;i++) {
str = str.replace('.','');
}
indices = [];
for(var i=0; i<str.length;i++) {
if (str[i] === ".") indices.push(i);
}
if (indices.length==0){
str = str.splice(str.length-2, 0, ".");
}
if (str[0]=='0' && str[1]!='.'){
str = str.replace('0','');
}
obj.value = str;
}
</script>