我有一个范围滑块,我想显示HTML画布上的范围滑块值,并且当范围滑块值更改时,该值应该在画布上始终更改。
slider.oninput = function() {
output.innerHTML = this.value; //this gets the range slider value every time it changes
var rangevalue = output.innerHTML; //and sends it to drawToCanvas function.
drawToCanvas(rangevalue);
}
范围值发送到drawToCanvas函数,但不在画布上显示。 Canvas显示“未定义”,我不知道为什么,因为drawToCanvas函数将rangevalue作为参数并将其存储到变量“ rangevalue”。当我在console.log上检查rangevalue的值时,该值是正确的,并且每次我在范围滑块上更改该值时都会更改,但是画布仍然显示“未定义”?
ctx.fillText(rangevalue, 50, 95); //here I try to show the value of rangevalue variable
答案 0 :(得分:0)
我没有这个问题,可能是drawToCanvas中的错字。
<input id="slider" type="range" max="1000000">
<div id="output"></div>
<canvas id="cnv" height="1000" width="1000"></canvas>
<script>
var ctx = cnv.getContext("2d")
slider.oninput = function() {
output.innerHTML = this.value; //this gets the range slider value every time it changes
var rangevalue = output.innerHTML; //and sends it to drawToCanvas function.
drawToCanvas(rangevalue)
}
function drawToCanvas(rangevalue){
ctx.clearRect(0, 0, 1000, 1000)
ctx.fillText(rangevalue, 100, 100)
}
</script>