how to set a value for select box code example

Example 1: javascript set html select value

// Get the html select element
var select = document.getElementById('<your select element id>');

// If you have a <option> like this:
// <option value="1">My Value Display text</option>

//Then your selected value of your select would be:

select.value = "1";

Example 2: javascript set select option

document.getElementById("mySelectID").value="my_value";
//note: setting value in html directly does not work <select value="my_value">