How to pass parameters through iframe from parent html?

On the main page simply pass parameters as follows

function myFunction(){
$('#myIframe').attr('src', "myIframeRequest.html?param1=value1&param2=value2"); 
} 

In Iframe

You can use a script to get the desired parameter value from parameters passed to page.

<script>
function getParamValue(paramName)
{
    var url = window.location.search.substring(1); //get rid of "?" in querystring
    var qArray = url.split('&'); //get key-value pairs
    for (var i = 0; i < qArray.length; i++) 
    {
        var pArr = qArray[i].split('='); //split key and value
        if (pArr[0] == paramName) 
            return pArr[1]; //return value
    }
}
</script>

Then you can fetch the value of desired parameter like this

var param1 = getParamValue('param1');