对于input

document.getElementById('input').value = 'status';

对于select

document.getElementById('select').value = 'taxis';

对于select multiple 

//selectElement.options[i].selected = true;

//提交到后台，接收到的是数组$week

//需要遍历每一个option分别判断再赋值 

<select multiple="" name="weekdays[]" id="selectid" class="form-control" required style="height: 168px;">
<?php foreach ($weekarr as $key => $val) {  ?>
<option value="<?php echo $key; ?>" ><?php echo $val; ?></option>
<?php } ?>
</select>

<script type="text/javascript">
var selectElement = document.getElementById('selectid');
var valuesToSelect = js_array;//数组
for (var i = 0; i < selectElement.options.length; i++) {
    var option = selectElement.options[i];
        if (valuesToSelect.includes(option.value)) {
            option.selected = true;
        } else {
            option.selected = false;
    }
}
</script>

//document.getElementById(id).checked = true;    

//checkbox，提交到后台，接收到的是数组$week。    

//需要遍历每一个checkbox项目并判断是否符合条件再赋值   

<style>
label{width:10%; text-align:center; margin:0 1%}
input[type=checkbox].label{display:none;}
input[type=checkbox].label + span{display:inline-block;background-color:#eee;padding:5px 8px;border-radius:15px;width:100%;cursor:pointer;}
input[type=checkbox].label:checked + span{background-color:#92e89d;}
input[type=file]{font-size:smaller;}
</style>

<label><input type="checkbox" name="week[]" id="week_0" class="label" value="0"><span>周日</span></label>
<label><input type="checkbox" name="week[]" id="week_1" class="label" value="1"><span>周一</span></label>
<label><input type="checkbox" name="week[]" id="week_2" class="label" value="2"><span>周二</span></label>
<label><input type="checkbox" name="week[]" id="week_3" class="label" value="3"><span>周三</span></label>
<label><input type="checkbox" name="week[]" id="week_4" class="label" value="4"><span>周四</span></label>
<label><input type="checkbox" name="week[]" id="week_5" class="label" value="5"><span>周五</span></label>
<label><input type="checkbox" name="week[]" id="week_6" class="label" value="6"><span>周六</span></label>

<script type="text/javascript">
var weekdays = [3,5];
var weekarr = [0,1,2,3,4,5,6];
for (var i = 0; i < weekarr.length; i++) {
    var id = 'week_' + i;
    var option = document.getElementById(id); 
    option.checked = weekdays.includes(weekarr[i]) ? true : false;
}
</script>