如何使用JavaScript函数获取HTML值

Question

I would like to set the value of a select-menu option to a value of a JavaScript object.

HTML

<select id="eRedList">
    <option value=electroSeries.Li.potential>Li</option>
</select>

JS

var electroSeries = {
    Li: {name : "Li", charge : "1", potential : -3.05, redReaction : "Li+(aq) + e- >> Li(s)", oxReaction : "Li(s) >> Li+(aq) + e-"};
}

so here, I want to the value associated with the property 'potential' to the HTML value. However, when I try to display this in a text box just to see what I get, I end up getting 'electroSeries.Li.potential' written instead of the numerical value.

I'm relatively new to JS, so any help would be appreciated!

Answer 1

Html and js cannot interact like you expect without an external library (like angular). You need to access your option element from the javascript and apply the value:

var electroSeries = {
    Li: {name : "Li", charge : "1", potential : -3.05, 
         redReaction : "Li+(aq) + e- >> Li(s)", 
         oxReaction : "Li(s) >> Li+(aq) + e-"};
}
var select = document.getElementById('eRedList');
select.options[0].value = electroSeries.Li.potential;

Edit: Solution based on comments

 var electroSeries = { Li: { potential : -3.05 }, K: { potential : -2.92 }, Ca: { potential : -2.76 }, }; var select = document.getElementById('eRedList'); for(var i in electroSeries) { var option = document.createElement('option'); option.innerHTML = i; option.name = i; option.value = electroSeries[i].potential; select.appendChild(option); } 

 Element: <select id="eRedList"></select>